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THE   UNIVERSITY 

OF   ILLINOIS 

LIBRARY 


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UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  185 


FIELD  EXPERIMENTS  IN  SPRAYING 
APPLE  ORCHARDS 


UNDER  THE  DIRECTION  OF 
J.  C.  BLAIE 

BY 

B.  S.  PICKETT 
O.  S.  WATKINS 
W.  A.  RUTH 
L.  E.  FOGLESONG 
A.  J.  GUNDEESON 


TJRBANA,  ILLINOIS,  FEBRUARY,  1916 


CONTENTS  OF  BULLETIN  No.  185 

PAGE 

Introduction     49 

Spraying  experiments  in  1910  at  Neoga,  Cumberland  county 58 

Spraying  experiments  in  1911  at  Neoga,  Cumberland  county 72 

Spraying  experiments  in  1912  at  Neoga,  Cumberland  county 88 

Spraying  experiments  in  1912  at  Flora,  Clay  county 104 

Spraying  experiments  in  1909  at  Griggsville,  Pike  county 118 

Spraying  experiments  in  1910  at  Centralia,  Marion  county 126 

Spraying  experiments  in  1911  at  Centralia,  Marion  county 130 

Spraying  experiments  in  1912  at  Anna,  Union  county 139 

Spraying  experiments  in  1911  at  Griggsville,  Pike  county 156 

Spraying  experiments  in  1912  at  Griggsville,  Pike  county 172 

GENERAL  SUMMARY 

Summary  of  Data 187 

Incidental  Observations   203 

Eecommendations    .                                                                                              .  204 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE 

ORCHARDS 

INTRODUCTION 

BY  B.  S.  PICKETT,  ASSISTANT  CHIEF  IN  POMOLOGY 

OBJECTS  OF  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 

The  apple  crop  is  subject  to  a  large  number  of  fungous  diseases 
and  to  depredations  from  many  insects.  In  the  state  of  Illinois  it 
commonly  happens  that  the  losses  from  some  one  or  more  of  these 
fungi  or  insects  amount  to  a  considerable  part  or  even  to  the  whole 
of  the  crop  in  any  one  season.  According  to  the  Thirteenth  Census 
of  the  United  States,  there  were  in  Illinois  in  1909,  9,900,627  apple 
trees  of  bearing  age,  producing  a  total  crop  of  over  3,093,321  bushels. 
While  this  low  production  per  tree  may  be  attributed  to  a  number  of 
causes,  the  most  serious  single  cause  for  the  reduction  of  the  crop  is 
to  be  found  in  failure  to  protect  the  trees  from  the  ravages  of  fungi 
and  insects.  During  the  summer  and  autumn  of  1912,  a  large  num- 
ber of  unsprayed  orchards  in  the  leading  orchard  sections  of  Illinois 
were  visited  by  the  writer,  and  in  no  case  was  there  found  any  fruit 
fit  for  barreling,  whereas  sprayed  orchards  in  the  same  localities  were 
bearing  abundant  crops  of  excellent  quality.  No  one  can  doubt  that 
attention  to  this  one  factor,  spraying,  in  apple  growing  would  easily 
increase  the  production  of  apples  in  Illinois  by  100  percent. 

The  chief  insects  affecting  the  fruit  of  the  apple  in  Illinois  are 
the  codling  moth  (Carpocapsa  pomonella),  the  plum  curculio 
(Conotrachelus  nenuphar],  and  the  San  Jose  scale  (Aspidiotus  per- 
niciosus).  The  foliage  is  attacked  by  a  number  of  insects,  such  as 
green  apple  aphis  (Aphis  mali),  canker  worm  (Paleacrita  vernata), 
fall  web-worm  (Hyphantria  cunea),  apple-leaf  miner  (Tischeria  mali- 
foliella),  pistol  case-bearer  (ColeopJiora  malivorella),  apple  flea-weevil 
(Or chest es  canus),  green  fruit  worms  (Xylina  antennata  et  al),  and 
many  others.  The  principal  diseases  affecting  the  fruit  of  the  apple 
are  apple  scab  (Venturia  inaequalis),  apple  blotch  (PJiyllosticta  soli- 
taria,  E.  &  E.),  sooty  blotch  (Leptofhyrium  pomi,  Mont.  &  Fr.),  fly- 
speck  (Leptothyrium  pomi,  Mont.  &  Fr.),  bitter  rot  (Glomerella  rufo- 
maculans),  and  cedar  rust  (Gymnosporangium  macropus).  Apple 

49 


50  BULLETIN  No.  185  [February, 

scab,  apple  blotch,  and  cedar  rust  also  attack  the  foliage.  Besides  these 
diseases  there  is  apple-leaf  spot,  or  frog-eye  fungus  (Spficeropsis 
malorum),  which,  tho  chiefly  destructive  to  the  foliage,  occasionally 
attacks  the  fruit  in  the  form  of  black  rot. 

It  has  long  been  understood  that  certain  chemicals  are  destructive 
to  the  spores  of  various  fungi ;  that  poisons  of  various  kinds,  but  more 
especially  substances  containing  arsenic,  will  kill  chewing  insects; 
and  that  certain  insects  which  do  not  chew  their  food  can  be  killed 
by  applying  some  substances  directly  to  their  bodies.  In  order  to 
ascertain  the  effectiveness  of  the  different  fungicides  and  insecticides 
which  have  been  advocated  or  suggested  in  many  quarters,  the  Horti- 
cultural Department  of  this  station  has  conducted  experiments  on  a 
large  scale,  under  field  conditions,  using  commercial  machinery,  and 
continuing  the  tests  from  year  to  year.  As  a  result  of  these  studies, 
bulletins  on  the  following  subjects  have  appeared:  "The  Curculio 
and  the  Apple,"  by  C.  S.  Crandall,  Bulletin  98;  "Spraying  Apples, 
Relative  Merits  of  Liquid  and  Dust  Applications, "  by  C.  S.  Crandall, 
Bulletin  106;  "Spraying  for  the  Codling  Moth,"  by  J.  W.  Lloyd, 
Bulletin  114;  "Bitter  Eot  of  Apples,"  by  J.  C.  Blair,  Bulletin  117; 
"Bitter  Rot  of  Apples,"  by  T.  J.  Burrill,  Bulletin  118;  "Bordeaux 
Mixture,"  by  C.  S.  Crandall,  Bulletin  135.  Each  of  these  pieces  of 
work  involved  a  special  study  of  some  one  phase  of  apple  spraying. 
In  later  experiments,  therefore,  it  became  the  purpose  of  the  depart- 
ment to  coordinate  the  results  of  earlier  investigations  into  general 
systems  of  spraying,  the  attempt  being  made  to  evolve  methods  of 
practice  which  would  be  practical  from  a  commercial  standpoint  and 
which  would  effectively  apply  to  the  solution  of  the  most  important 
spraying  problems.  With  this  idea  in  view  an  effort  was  made  to 
answer  the  following  questions  thru  the  medium  of  the  field  experi- 
ments : 

1.  What  is  the  general  effectiveness  of  applications  of  standard 
spray  mixtures,  including  Bordeaux,  lime  sulfur,   and  arsenate  of 
lead,  in  the  control  of  fungi  and  insects  on  the  apple? 

2.  What  are  the  relative  values  of  Bordeaux  and  lime  sulfur  as 
sprays  for  the  apple  ? 

3.  Can  Bordeaux  injury  be  lessened  or  prevented  by  frequent 
sprayings  with  the  same  spray,  or  by  maintaining  over  the  Bordeaux 
a  coating  of  lime  thruout  the  season? 

4.  Is  it  possible  to  interchange  Bordeaux  and  lime  sulfur,  in  a 
spray  schedule,  to  advantage,  using  Bordeaux  for  one  or  more  ap- 
plications and  lime  sulfur  for  the  remaining  applications? 

5.  What  is  the  most  effective  and  at  the  same  time  the  most  eco- 
nomical dilution  of  lime  sulfur  as  a  fungicide  spray? 

6.  Is  homemade  concentrated  lime  sulfur  as  efficient  as  the  ordi- 
nary commercial  concentrated  lime  sulfur  ? 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  51 

7.  What  is  the  fungicidal  value  of  self-boiled  lime  sulfur,  and 
how  does  it  compare  with  lime  sulfur  made  in  the  usual  manner? 

8.  Will  the  addition  of  copper  sulfate  to  lime  sulfur  increase  the 
fungicidal  value  of  the  spray? 

9.  Is  an  application  of  lime  sulfur  made  at  the  strength  used  for 
San  Jose  scale,  applied  while  the  trees  are  dormant,  of  any  value  as  a 
preventive  of  apple  scab  ? 

10.  What  is  the  most   effective   poison   which   can   be   advan- 
tageously combined  with  standard  fungicides  for  the  control  of  chew- 
ing insects,  particularly  the  codling  moth  and  the  plum  curculio? 

11.  Does  arsenate'  of  lead  when  used  alone  possess  any  fungicidal 
value  ? 

12.  Does  arsenate  of  lead  when  added  to  Bordeaux  or  lime  sulfur 
increase  their  fungicidal  value? 

13.  Are  there  differences  between  various  brands  of  arsenate  of 
lead  which  would  make  one  brand  more  useful  than  another,  either 
alone  or  in  combination  with  the  standard  fungicides  ? 

14.  Of  what  value  are  certain  new  sprays,  both  as  fungicides  and 
as  insecticides? 

15.  How  often  and  at  what  times  should  summer  sprays  be  ap- 
plied ? 

ORGANIZATION 

The  attempt  to  answer  these  various  questions  for  the  several  lead- 
ing orchard  sections  of  the  state  required  the  organization  of  the  work 
on  a  large  scale.  In  order  to  secure  results  which  would  be  thor- 
oly  reliable,  it  was  deemed  necessary  to  make  field  experiments  in 
each  of  the  leading  orchard  sections ;  viz.,  in  the  extreme  western  part 
of  the  state,  in  the  extreme  southern  part  of  the  state,  and  in  the 
orchard  section  in  the  gray-soil  region  which,  in  a  general  way,  cen- 
ters about  the  counties  of  Marion,  Clay,  and  Richland.  In  order  to 
counteract  seasonal  differences,  it  was  planned  to  conduct  experi- 
ments in  these  sections  for  several  successive  years,  and  with  one  ex- 
ception this  plan  was  followed.  In  the  results  which  are  given  in  this 
bulletin  there  are  presented  the  data  derived  from  four  years '  experi- 
mentation. In  the  course  of  these  four  years,  experiments  were  car- 
ried on  at  five  different  points,  in  ten  series  of  plats,  in  seven  differ- 
ent orchards. 

Obstacles  and  difficulties  along  the  following  lines  presented  them- 
selves in  one  form  or  another  at  various  times  thruout  the  experi- 
mental work: 

1.  The  climatic  conditions  in  different  parts  of  the  state  vary  to 
a  considerable  extent,  thus  making  it  hard  to  summarize  and  average 
results  for  any  particular  season. 

2.'  It  is  nearly  always  difficult  to  secure  orchards  of  uniformly 
vigorous  growth  with  trees  arranged  in  such  a  manner  that  the  vari- 
eties in  each  plat  will  be  comparable  with  those  in  adjoining  plats. 


52  BULLETIN  No.  185  [February, 

3.  Uniform  conditions  in  regard  to  age  of  trees,  slope,  and  drain- 
age are  difficult  to  obtain,  particularly  in  conjunction  with  other  re- 
quirements calling  for  absolute  uniformity. 

4.  A  reasonably  uniform  infection  of  diseases  or  infestation  of 
insects  is  necessary  to  insure  reliable  results,  a  matter  extremely  dif- 
ficult to  determine  before  an  experiment  is  commenced.     Certain 
fungi  and  certain  insects  cannot  be  expected  to  distribute  themselves 
uniformly,  and  special  methods  must  be  adopted  in  the  arranging  of 
plats  and  checks  to  avoid  errors  in  the  study  of  the  control  of  these 
particular  pests. 

5.  The  making  of  uniform  records  of  experiments  in  spraying  is 
extremely  difficult.     Different  observers  are  apt  to  attach  different 
degrees  of  importance  to  the  various  points  on  which  data  are  to  be 
obtained. 

6.  Many  things  which  materially  affect  results  in  spraying  ex- 
periments are  easily  passed  over.     Successful  spraying  depends  so 
much  upon  detail  in  the  correct  preparation  of  mixtures,  in  the  proper 
agitation  of  the  mixture  in  the  spray  tank,  in  the  careful  and  thoro 
application  to  the  trees,  and  on  the  weather  conditions  which  prevail 
not  only  at  spraying  time  but  thruout  the  entire  following  season, 
that  results  may  readily  be  obtained  which  can  be  accounted  for  only 
in  the  light  of  all  the  conditions  prevailing  thruout  the  experiment. 

The  organization  for  work  in  these  field  experiments  in  spraying 
apple  orchards  was  designed  particularly  to  avoid  or  to  counteract 
the  difficulties  which  it  was  felt  certain  would  be  met.  Especial  care 
was  exercised  in  choosing  orchards  which  were  representative  of  the 
sections  in  which  they  were  located,  which  were  uniform  as  to  variety, 
age,  vigor  of  trees,  and  previous  soil  and  spraying  treatment,  and 
which  were  of  such  size  and  form  as  would  permit  laying  out  experi- 
mental plats  to  advantage.  The  men  in  charge  of  these  experiments 
were  all  graduates  of  the  University  of  Illinois,  or  were  trained  in 
the  Department  of  Horticulture  at  this  university.  All  the  men  were 
taught  similar  methods  of  preparing  the  standard  spray  mixtures 
used  in  the  experiments  and  all  were  familiar  with  the  types  of  spray 
apparatus  used.  The  results  of  the  data  gathered  were  freely  dis- 
cussed by  all  the  men  concerned,  and  from  year  to  year,  suggestions 
were  made  for  the  better  recording  of  data  and  for  new  lines  of  work. 
Thus  each  succeeding  year's  work  has  been  carried  forward  in  the 
light  of  the  experience  of  past  years. 

The  accompanying  map  shows  the  location  of  the  Agricultural  Ex- 
periment Station  at  Urbana,  and  of  the  various  experiments  conducted 
during  the  last  four  years. 

Detailed  descriptions  of  the  orchards  are  given  under  the  reports 
of  each  experiment. 

The  following  tabulation  gives  the  location  of  the  experiments  and 
the  names  of  the  men  in  charge : 


1916} 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


53 


CHART  1. — MAP  OF  ILLINOIS,  SHOWING  THE  LOCATION  OP  THE  AGRICULTURAL  EX- 
PERIMENT STATION  AND  OF  THE  VARIOUS  EXPERIMENTAL  ORCHARDS 


54 


BULLETIN  No.  185 
LOCATION  OF  EXPERIMENTS  AND  MEN  IN  CHARGE 


[February, 


Year 

Place 

County 

Horticultural 
division 

Owner  of  orchard 

In  charge  of 
orchard 

1909 

Griggsville 

Pike 

Western  Central 

Mr.  John  Sawdon 

L.  Earl  Foglesong 

1910 

Centralia 

Marion 

Southern 

G.  H.  Perrine  &  Sons 

L.  Earl  Foglesong 

1910 

Neoga 

Cumberland 

Southern 

H.  A.  Aldrieh  &  Co. 

O.  S.  Watkins 

1911 

Centralia 

Marion 

Southern 

G.  H.  Perrine  &  Sons 

L.  Earl  Foglesong 

1911 

Neoga 

Cumberland 

Southern 

H.  A.  Aldrieh  &  Co. 

O.  S.  Watkins 

1911 

Griggsville 

Pike 

Western  Central 

Mr.  G.'Warton 

Alfred  J.  Gunderson 

1912 

Anna 

Union 

Southern 

Mr.  F.  P.  Anderson 

L.  Earl  Foglesong 

1912 

Neoga 

Cumberland 

Southern 

H.  A.  Aldrieh  &  Co. 

O.  S.  Watkins 

1912 

Griggsville 

Pike 

Western  Central 

Mr.  F.  Turnbull 

Alfred  J.  Gunderson 

1912 

Flora 

Clay 

Southern 

Mrs.  John  Egginton 

W.  A.  Kuth 

STANDARD  SPRAYS:  FORMULAS  AND  PREPARATION 

The  standard  sprays  used  thruout  these  experiments  were  Bor- 
deaux, lime  sulfur,  and  arsenate  of  lead.  In  all  cases  thruout  this  bul- 
letin where  the  formulas  and  preparation  are  not  distinctly  described 
in  connection  with  the  sprays  spoken  of,  the  sprays  were  prepared  as 
here  described. 

Bordeaux. — Eight  pounds  copper  sulfate,  8  pounds  freshly-slaked 
lump  lime,  100  gallons  water.  Except  in  the  case  of  the  experiments 
at  Flora  in  1912,  the  mixture  was  prepared  by  dissolving  the  copper 
sulfate  in  half  the  total  quantity  of  water  used,  and  mixing  the  slaked 
lime  with  the  other  half.  The  diluted  solution  and  the  diluted  mix- 
ture were  then  poured  together  simultaneously  thru  a  sieve,  either 
into  the  mixing  tank  or  directly  into  the  spray  tank. 

Lime  Sulfur,  Commercial,  for  Summer  Sprays. — Eight  pounds 
sulfur  in  100  gallons  spray  (3  gallons  commercial  concentrated  lime 
sulfur  to  97  gallons  water,  or  3  gallons  commercial  concentrated  lime 
sulfur  in  100  gallons  of  the  dilute  summer  spray) . 

Lime  Sulfur,  Homemade,  for  Summer  Sprays. — Eight  pounds  sul- 
fur in  100  gallons  spray  (5%  gallons  stock  solution  homemade  lime 
sulfur  to  94i/k  gallons  water,  or  5~y2  gallons  stock  solution  homemade 
lime  sulfur  in  100  gallons  spray). 

Lime  Sulfur,  Homemade,  for  Dormant  Spray. — Twenty-nine 
pounds  sulfur  in  100  gallons  spray  (20  gallons  stock  solution  home- 
made lime  sulfur  to  80  gallons  water,  or  20  gallons  stock  solution 
homemade  lime  sulfur  in  100  gallons  spray). 

Stock  Solution,  Homemade  Lime  Sulfur. — One  hundred  pounds 
sulfur,  50  pounds  lime,  water  to  make  66  gallons.1  Homemade  lime 
sulfur  was  prepared  by  placing  in  a  large  kettle  15  gallons  water  and 
50  pounds  good  lime,  free  from  air-slaked  particles.  When  the  lime 
was  slaking  vigorously,  100  pounds  of  powdered  sulfur  were  poured 
in,  and  mixed  thoroly  with  the  lime.  Sufficient  water  was  added 
gradually  to  prevent  the  lime  from  drying  out  during  the  process  of 
THinois  formula. 


1916}  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  55 

slaking.  As  soon  as  the  lime  was  thoroly  slaked  and  the  sulfur  thoroly 
mixed,  enough  water  was  added  to  bring  the  total  volume  to  66  gal- 
lons or  a  little  more.  Boiling  was  continued  for  30  to  45  minutes, 
water  being  added  from  time  to  time  to  keep  the  rolume  at  66  gallons. 
By  following  this  method  it  was  found  possible  to  get  the  maximum 
amount  of  sulfur  into  solution.  In  most  of  the  experimental  work, 
the  boiling  was  done  in  large  iron  kettles  heated  over  simple  outdoor 
fireplaces  constructed  for  the  purpose.  In  the  experiments  at  Cen- 
tralia,  however,  the  homemade  lime  sulfur  was  obtained  from  the 
cooking  plant  of  G.  H.  Perrine  and  Sons. 

Arsenate  of  Lead. — Four  pounds  arsenate  of  lead  paste  in  100  gal- 
lons water,  Bordeaux,  or  lime  sulfur.  The  arsenate  of  lead  was  worked 
up  with  a  small  quantity  of  water  into  a  mixture  that  would  pour 
readily  and  mix  evenly  with  the  water  or  fungicide  when  subjected 
to  the  action  of  the  agitator  in  the  spray  tank. 

TIMES  OP  APPLICATION 

Thruout  this  bulletin  applications  are  spoken  of  as  dormant-tree, 
or  winter  sprays,  and  first,  second,  third,  fourth,  fifth,  and  sixth  sum- 
mer sprays. 

The  dormant-tree,  or  winter,  application,  refers  to  the  spray  ap- 
plied particularly  for  the  control  of  San  Jose  scale,  and  always  con- 
sists of  lime  sulfur  at  the  dilutions  mentioned  under  the  preceding 
section.  It  may  be  applied  at  any  time  after  the  trees  shed  their 
leaves  in  the  fall  and  before  the  buds  show  green  in  the  spring. 
Usually,  however,  this  application  is  made  during  March. 

The  summer  sprays  are  not,  strictly  speaking,  summer  sprays,  as 
the  first  three  are  usually  applied  during  April  and  May.  They  are 
referred  to  as  summer  sprays  as  a  matter  of  convenience,  because  all 
are  applied  after  leaf  growth  has  started.  The  first  of  these  is  com- 
monly referred  to  as  the  cluster-bud  spray,  because  it  is  made  after 
the  cluster  buds  open  and  the  individual  flower  buds  within  the  clus- 
ter buds  have  separated  slightly  from  each  other.  The  second  spray 
is  made  immediately  after  the  fall  of  the  petals  and  while  the  lobes  of 
the  calyx  cups  are  still  distended.  At  this  time  the  calyx  cups  point 
upward  or  outward  rather  than  downward.  The  third  summer  spray 
is  made  about  ten  days  after  the  second.  Later  summer  sprays  are 
made  for  the  control  of  the  second  brood  of  codling  moth,  for  bitter 
rot,  and,  in  some  cases,  for  apple  blotch.  The  spray  for  the  second 
brood  of  codling  moth  is  applied  from  July  1  to  10  in  the  extreme 
southern  portion  of  the  state,  from  July  4  to  12  in  the  apple  region 
included  in  Marion,  Clay,  Richland,  and  adjoining  counties,  and  from 
that  time  until  the  middle  of  August  at  the  extreme  northern  part  of 
the  state,  depending  somewhat  upon  the  season. 


56  BULLETIN  No.  185  [February, 

Sprays  for  bitter  rot  are  commenced  during  the  last  week  in  June, 
if  the  disease  is  anticipated,  and  continued  at  intervals  of  ten  days 
until  four  applications  have  been  made.  If  a  separate  spray  is  re- 
quired for  apple  blotch,  it  may  be  applied  ten  days  to  two  weeks  after 
the  third  regular  summer  spray,  or  about  four  weeks  after  the  fall  of 
the  petals. 

TERMINOLOGY  ;  DEFINITIONS  ;  MISCELLANEOUS  EXPLANATIONS 

Bordeaux. — The  term  "Bordeaux"  is  used  thruout  this  bulletin  in 
place  of  the  term  heretofore  applied,  viz.,  Bordeaux  mixture.  The 
authors  feel  that  in  connection  with  the  literature  on  spraying  the 
term  is  now  so  well  understood  that  there  is  no  necessity  for  the  use 
of  the  longer  name.  It  must,  moreover,  be  used  with  so  great  fre- 
quency in  a  publication  of  this  kind  that  the  omission  of  the  word 
"mixture"  may  be  justified  on  the  ground  of  convenience. 

Combined  Fungicides  and  Insecticides. — When  Bordeaux,  lime 
sulfur,  or  other  fungicides  have  been  used  in  combination  with  arsen- 
ate  of  lead  or  other  insecticides,  the  names  of  the  insecticide  and  the 
fungicide  are  written  consecutively  without  separation  by  means  of  a 
hyphen  or  other  punctuation ;  as,  Bordeaux  arsenate  of  lead,  and  lime 
sulfur  arsenate  of  lead. 

Bordeaux  Injury  to  Foliage. — Bordeaux  injuries  to  foliage  may 
be  in  the  form  of  a  yellowing  of  the  leaves,  or  in  the  killing  of  por- 
tions of  the  leaf  which  turn  brown  and  become  dry.  These  dead 
patches  appear  along  the  margins  of  the  leaves  or  near  their  tips, 
where  the  spray  mixtures  accumulate  in  considerable  quantities,  or 
in  spots  distributed  over  the  leaf.1 

Yellow-Leaf. — Trees  affected  by  yellow-leaf  show  premature  yel- 
lowing of  the  foliage.  Usually  only  a  comparatively  small  number 
of  the  leaves  lose  their  color,  but  in  severe  cases  one-fourth  to  one- 
third  of  all  the  foliage  is  lost.  In  most  cases  the  injury  is  directly 
traceable  to  the  use  of  Bordeaux  as  a  spray ;  occasionally  it  seems  to 
be  due  to  some  physiological  cause  not  well  understood.  When  it  is 
caused  by  Bordeaux  the  leaves  do  not  turn  yellow  immediately  upon 
the  application  of  the  spray.  The  injury  becomes  noticeable  in  from 
one  to  two  weeks  after  the  application  of  the  fungicide,  or  appears 
even  after  an  interval  of  several  weeks. 

Lime-Sulfur  Injury  to  Foliage. — Lime  sulfur  appears  to  kill 
patches  on  the  margins  of  the  leaves  or  near  their  tips,  but  yellowing 
of  the  foliage  as  a  result  of  the  use  of  lime  sulfur  does  not  occur. 

Lime-Sulfur  Burn  or  Scald. — Apples  sprayed  with  lime  sulfur, 
particularly  during  extremely  hot  weather,  suffer  occasionally  from  a 
form  of  injury  known  as  burn,  or  scald.  This  injury  appears  on  the 
sunny  side  of  the  fruit,  frequently  toward  the  stem  end  or  in  the 

'Bordeaux  Mixture,  C.  S.  Crandall,  111.  Agr.  Exp.  Sta.  Bui.  135,  p.  220. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  57 

cavity,  if  the  cavity  is  exposed  to  the  sun.  The  injury  takes  the  form 
of  a  browning  of  the  skin  and  of  the  tissues  immediately  beneath  the 
skin.  It  may  even  extend  to  the  center  of  the  apple.  In  severe  cases 
the  affected  part  of  the  apple  splits  across,  sometimes  in  both  direc- 
tions, forming  a  cross-shaped  incision.  When  the  injury  is  only  su- 
perficial, it  sometimes  heals  beneath  the  injured  skin,  which  sloughs 
off  as  the  new  epidermis  grows  just  beneath  it  and  displaces  it.  Thru- 
out  these  experiments  lime-sulfur  burn  was  common  only  during  the 
extremely  hot  summer  of  1911 ;  during  the  seasons  of  1910  and  1912 
it  was-  recorded  but  rarely. 

Russeting  of  the  Fruit. — "Russeting"  is  a  term  descriptive  of  the 
appearance  of  portions  of  the  skin  of  apples  which  normally  should 
be  smooth,  and  red  or  yellow  in  color.  The  apple  may  be  affected  in 
varying  degrees  of  severity.  In  the  milder  forms  russeting  appears 
as  a  few  fine  russeted  lines  which  spread  themselves  in  a  sort  of  net- 
work over  larger  or  smaller  parts  of  the  surface  of  the  apple,  or  it 
may  appear  as  small  black  dots  which  give  to  the  skin  of  the  apple 
a  rough  appearance  and  feel.  In  cases  of  moderate  severity  russeted 
patches  of  considerable  size  appear  on  the  fruit,  with  lines  of  russet- 
ing spreading  out  from  them.  Very  severe  russeting  may  cause  de- 
formed fruits  and  render  the  crop  worthless  except  for  bulk  or  cider 
stock.  Russeting  appears  to  be  caused  by  any  irritation  to  the  skin 
of  the  fruits.  It  very  frequently  follows  the  application  of  Bordeaux 
and  other  sprays  to  which  copper  sulfate  has  been  added.  It  is  also 
recorded  as  occurring  to  some  extent  after  applications  of  lime  sulfur ; 
not  infrequently  it  is  observed  where  no  sprays  whatever  have  been 
applied. 

ARRANGEMENT  OF  SUBJECT  MATTER 

The  data  for  each  series  of  field  experiments  in  spraying  are  given 
in  separate  reports.  It  will  be  noted  that  there  is  a  decided  similar- 
ity between  the  results  from  the  various  series,  but  it  is  not  to  be 
expected  that  each  series  will  in  every  detail  corroborate  the  results 
of  every  other  series.  The  data  are  presented,  therefore,  with  suffi- 
cient detail  to  show  the  scientific  accuracy  of  the  work  and  at  the  same 
time  to  make  the  results  of  permanent  value,  both  to  the  commercial 
orchardist  and  to  the  investigator  interested  in  studying  the  problems 
of  insect  and  fungus  control  from  either  a  practical  or  scientific  stand- 
point. In  addition  to  a  summary  which  is  generally  made  at  the  end 
of  each  report,  a  final  summary  at  the  end  of  the  bulletin  brings 
together  the  general  results  of  the  four  years'  experimentation  and 
includes  recommendations  for  spraying  practice  in  Illinois  apple 
orchards. 


58  BULLETIN  No.  185  [February, 


BY  O.  S.  WATKINS,  ASSOCIATE  IN  HORTICULTURAL  CHEMISTRY 
OBJECTS 

During  the  summer  of  1910,  spraying  experiments  were  under- 
taken at  Neoga,  Illinois,  the  chief  lines  of  investigation  being  tests  to 
determine:  (1)  the  relative  efficiency  of  lime-sulfur  mixtures  and 
Bordeaux;  (2)  the  efficiency  of  Bordeaux  and  milk  of  lime  in  reduc- 
ing Bordeaux  injury;  (3)  the  comparative  values  of  various  commer- 
cial arsenates  of  lead.  On  a  fourth  group  treatment  was  begun  to  test 
the  value  of  certain  new  and  proprietary  sprays,  including  Pyrox, 
Sulfocide,  Cucasa,  arsenic  sulfid,  copper  ferrocyanide,  and  Black 
Leaf  40,  but  owing  to  unfavorable  weather  conditions,  no  fruit  data 
were  obtained  on  any  of  the  plats  in  this  group. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

The  orchard  selected  for  these  experiments  is  situated  two  miles 
southwest  of  Neoga  and  is  owned  by  H.  A.  Aldrich  and  Company  of 
that  town.  It  consisted  of  twenty  acres  of  several  varieties  of  trees, 
of  which  three  hundred  fifteen-year-old  Ben  Davis  trees  planted  in  a 
solid  block  were  chosen  for  the  experiment.  The  land  upon  which  the 
orchard  is  located  is  more  or  less  rolling,  and  a  small  stream  passes 
thru  it.  The  trees  were  in  vigorous  condition,  having  been  given  ex- 
cellent care  ever  since  they  were  planted. 

ARRANGEMENT  OF  PLATS 

The  experimental  block  was  divided  into  plats  of  four  to  six  trees 
each,  and  the  various  plats  were  sprayed  differently.  Scattered  among 
the  plats,  check  trees,  which  were  given  no  treatment,  were  kept  for 
comparison  with  the  sprayed  trees.  Problems  of  similar  nature  were 
grouped  together,  and  in  no  group  were  there  more  trees  than  could 
be  sprayed  in  a  single  day. 

APPARATUS  AND  MATERIALS 

All  spray  mixtures  were  made  according  to  the  methods  recom- 
mended by  the  Illinois  Agricultural  Experiment  Station,  and  are 
given  in  brief  under  the  several  groups.  Owing  to  the  large  number 
of  different  sprays  which  were  used  and  the  small  amount  of  each 
which  was  required,  the  material  was  applied  by  means  of  a  barrel 
pump  at  100  to  125  pounds  pressure.  Vermorel  nozzles  were  used. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


59 


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60  BULLETIN  No.  185  [February, 

CHARACTER  OF  RECORDS  AND  METHOD  OF   MAKING 

Foliage  notes  were  taken  from  time  to  time  thruout  the  season, 
and  the  dropped  apples  were  counted  and  examined.  All  fruit  upon 
the  trees  at  harvesting  time  was  hand-picked,  counted,  and  weighed. 
Owing  to  the  generally  small  yield  of  fruit,  practically  the  entire  crop 
was  examined.  On  a  few  plats  certain  trees  bore  a  full  crop,  and  in 
such  cases,  a  representative  tree  was  chosen,  and  all  the  apples  on  a 
certain  portion  of  it,  including  those  on  the  lowest  and  uppermost 
branches  and  those  on  the  outermost  and  innermost  branches  of  the 
tree,  were  picked  and  placed  on  the  sorting  table.  From  these,  two 
samples  of  one  hundred  each  were  chosen  and  examined  separately 
and  the  records  compared.  In  case  the  records  were  not  approx- 
imately the  same,  another  sample  of  one  hundred  apples  was  selected 
and  examined,  and  this  process  was  repeated  until  the  records  were 
obtained  upon  an  average  sample.  The  results  recorded  are  the  aver- 
age of  all  samples  examined. 

In  examining  the  apples  for  blemishes,  a  record  was  kept  of  all 
markings,  however  small;  in  grading  the  standard  adopted  by  the 
Illinois  State  Horticultural  Society  was  adhered  to.1  The  grade  rec- 
ords were  taken  from  the  samples  examined,  and  the  percentages  are 
based  on  the  number  of  apples  in  each  grade.  This  makes  the  per- 
centage of  No.  2's  and  culls  somewhat  larger  than  would  be  the  case 
had  the  grading  been  in  terms  of  bushels. 

WEATHER   CONDITIONS 

The  season  was  quite  abnormal.  March  was  a  warm  month,  and 
as  a  result  the  trees  came  into  blossom  early  in  April,  nearly  a  month 
before  the  average  normal  blooming  date.  A  very  heavy  bloom  was 
followed  by  an  excellent  set  of  fruit,  but  on  April  23,  when  the  apples 
had  reached  the  size  of  hazel  nuts,  many  of  the  small  ones  were 
frozen.  Perhaps  15  to  20  percent  of  the  crop  in  the  experimental 
orchard  survived  the  cold.  The  season  was  normal  as  regards  rain- 
fall, seldom  more  than  ten  days  intervening  between  rains  of  one-half 
inch  or  more. 

DISEASES  AND  INSECTS 

The  infection  of  apple  scab  could  not  have  been  worse,  altho  the 
fungus  did  not  appear  until  about  the  middle  of  May,  when  the  apples 


"'For  Ben  Davis,  a  No.  1  apple  shall  not  be  less  than  2y2  inches  in  diameter, 
shall  be  practically  free  from  action  of  worms,  or  not  over  10  percent  of  the  apples 
affected  by  scab  or  other  defacement  of  surface;  shall  be  hand-picked  from  the 
trees  and  not  bruised,  or  skin-broken;  shall  be  of  a  bright  and  normal  color  and 
shapely  formed.  No.  2  apples  may  be  2^4  inches  in  diameter,  and  not  over  20 
percent  of  the  apples  affected  by  defacement  of  surface  by  dry  rot,  scab,  worms, 
or  other  defects;  shall  be  hand-picked  from  the  trees  and  not  bruised  or  skin- 
broken  ;  shall  be  of  a  bright  and  normal  color  and  shapely  formed.  Adopted 
December  17,  1903." 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  61 

were  the  size  of  hickory  nuts.  There  was  also  an  abundance  of  insects. 
Neighboring  orchards  which  received  no  care  produced  no  fruit  and 
were  defoliated  before  the  first  of  September. 

SPRAY  DATES 

The  entire  orchard  was  given  a  winter  application  of  lime  sulfur 
the  latter  part  of  March,  just  as  the  buds  were  beginning  to  swell; 
and  from  one  to  six  summer  applications  of  various  sprays  were  made 
upon  or  near  the  following  dates :  April  7,  April  26,  May  10,  May  27, 
June  21,  and  July  22. 

RELATIVE  EFFICIENCY  OF  LIME  SULFUR  AND  BORDEAUX 

During  the  last  few  years  lime  sulfur  has  attracted  attention  as 
a  fungicide  for  the  summer  treatment  of  apples.  In  order  to  deter- 
mine the  adaptability  of  this  spray  for  Illinois  orchards  five  plats, 
each  consisting  of  sixteen  trees,  and  subdivided  into  plats  of  four 
trees  each,  were  sprayed  as  follows: 

Plat  A:  Homemade  lime  sulfur.  This  was  made  by  boiling  together,  until 
all  the  sulfur  was  in  solution,  10  pounds  of  lime,  20  pounds  of  sulfur,  and  about 
13  gallons  of  water.  This  solution  was  then  diluted  so  that  100  gallons  of  spray 
contained  8  pounds  of  sulfur.1  The  material  was  made  up  immediately  before 
each  application. 

Plat  B :  Home-concentrated  lime  sulfur.  This  was  made  by  boiling  together, 
until  all  the  sulfur  was  in  solution,  50  pounds  of  lime,  100  pounds  of  sulfur,  and  50 
gallons  of  water.  This  solution  was  diluted  so  that  100  gallons  of  spray  contained 
8  pounds  of  sulfur.2  The  material  was  prepared  early  in  the  season  and  kept 
as  a  stock  solution,  some  of  it  being  used  for  each  application.  In  order  to  deter- 
mine whether  or  not  there  was  any  deterioration  of  home-concentrated  lime-sulfur 
solution  upon  standing,  the  records  obtained  upon  the  fruit  in  these  plats  were 
compared  with  those  from  the  A  plats. 

Plat  C:  Self -boiled  lime  and  sulfur.  This  was  made  from  32  pounds  of 
lime,  32  pounds  of  sulfur,  and  200  gallons  of  water.  The  preparation  of  this  spray 
differs  from  that  used  on  Plats  A  and  B,  in  that  the  only  heat  used  to  cook  it  is 
that  furnished  by  the  slaking  lime. 

Plat  D :     Commercial  lime  sulfur,  1  in  35. 

Plat  E :     Standard  Bordeaux,  8-8-100. 

For  the  control  of  chewing  insects,  arsenate  of  lead  was  added  to  each  of  the 
above  mixtures  at  the  rate  of  4  pounds  per  100  gallons  of  spray. 

EFFECT  ON  FOLIAGE 

The  early  effects  of  the  first  three  applications  were  quite  similar. 
The  first  infection  of  scab  did  not  occur  until  several  days  after  the 
third  application  of  spray  had  been  made.  Shortly  after  this  appli- 
cation, there  was  considerable  rain,  which  washed  off  much  of  the 
spray  and  at  the  same  time  afforded  excellent  conditions  for  the  germ- 
ination of  scab  spores.  At  the  time  the  scab  appeared  there  was  very 

1Based  on  analyses  of  similarly  made  solutions. 
2Based  on  analyses  of  solutions  used. 


62  BULLETIN  No.  185  [February, 

little  spray  material  visible  upon  any  of  the  trees  which  had  been 
sprayed  with  the  lime-sulfur  mixtures,  while  there  was  a  large  amount 
visible  on  the  trees  in  Plat  E,  which  had  received  Bordeaux.  Plats 
A,  B,  C,  and  D  were  almost  as  badly  infected  with  scab  as  were  the 
check  trees,  whereas  Plat  E  showed  very  little  scab. 

With  the  exception  of  the  self-boiled  lime  and  sulfur,  the  later 
applications  of  the  lime-sulfur  sprays  checked  to  a  considerable  ex- 
tent the  work  of  the  scab,  but  at  the  same  time  caused  much  foliage 
injury.  This  injury  was  along  the  edges  and  at  the  tips  of  the  leaves 
and  in  the  scab  spots;  the  later  the  application  the  more  severe  was 
the  injury.  The  influence  of  the  self -boiled  lime  and  sulfur  in  the 
control  of  scab  was  very  temporary;  however,  no  spray  injury  fol- 
lowed its  use.  Bordeaux  proved  very  adhesive,  controlled  the  scab 
almost  perfectly,  and  caused  but  little  foliage  injury.  Of  the  five 
sprays  used,  Bordeaux  proved  the  most  efficient  in  protecting  the 
foliage  from  scab,  and  self-boiled  lime  and  sulfur  the  least  effective. 
All  the  cooked  lime-sulfur  sprays  possessed  considerable  fungicidal 
value,  but  because  of  their  lack  of  adhesiveness  their  action  was  only 
temporary. 

In  spite  of  the  fact  that  self -boiled  lime  and  sulfur  possesses  very 
little  fungicidal  value  in  the  control  of  apple  scab,  the  plat  sprayed 
with  this  material  (Plat  C)  deserves  special  attention  because  of  the 
fact  that  the  general  appearance  of  the  trees  at  a  distance  was  much 
better  than  that  of  any  of  the  others  under  consideration.  These  trees 
were  distinguished  by  the  large  size,  the  dark  color,  and  the  abundance 
of  their  foliage.  They  did  not  suffer  so  severely  from  the  freeze  as 
the  others,  since  the  application  of  lime  and  sulfur  made  April  22 
formed  a  coating  over  the  fruit  and  foliage  which  acted  in  some  way 
as  a  shield  against  the  cold. 

EFFECT  ON  FRUIT 

On  all  plats  some  fruit  survived  the  freeze  of  April  23  except  on 
Plat  E,  upon  which  Bordeaux  had  been  used.  As  this  plat  was  sit- 
uated in  the  western  part  of  the  orchard,  adjoining  an  open  field,  only 
a  very  few  apples  escaped  being  frozen. 

Table  1  shows  the  relative  fungicidal  value  of  different  lime-sulfur 
sprays  in  the  control  of  scab  on  the  fruit,  and  also  the  benefits  de- 
rived from  three,  four,  five,  and  six  applications.  These  results  fully 
corroborate  those  secured  upon  the  foliage,  as  stated  above.  Unfor- 
tunately there  were  no  Bordeaux-sprayed  apples  directly  comparable 
with  the  fruit  sprayed  with  lime  sulfur,  but  judging  from  the  effect  of 
the  Bordeaux  upon  the  foliage,  much  less  scab  might  be  expected  upon 
the  fruit  sprayed  with  that  material.  The  apples  from  the  B  plats 
(sprayed  with  home-concentrated  lime  sulfur)  showed  somewhat  less 
scab  than  those  from  the  other  plats,  but  even  upon  these  the  amount 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


63 


TABLE  1. — EFFECTS  OF  LIME  SULFUR,  SELF-BOILED  LIME  SULFUR,  AND  BORDEAUX  IN 
COMBINATION  WITH  ARSENATE  OF  LEAD,  IN  THE  EXPERIMENTS  AT  NEOGA,  1910 


CO 

Percentage  of  picked 

oH 

apples  affected  by 

Plat 

Treatment 

Applications 

^H     * 

o 

*3 

W) 

.35 

.. 

"o  « 

ft 

w 

i—  i    o 

• 

EH  "o 

§ 

M 

0    S 

§ 

U 

so 

u 

u 

PH 

A, 

10-20-13  lime  sulfur  di- 

1,2,3 

139 

94 

16 

3.6 

13 

A, 

•  luted  1  in  18  with  4- 

1,  2,  3,  4 

33 

81 

24 

3.0 

18 

A, 

100  arsenate  of  lead. 

1,  2,  3,  4,  5 

42 

60 

17 

2.5 

10 

A< 

1,  2,  3,  4,  5,  6 

77 

32 

24 

2.6 

5 

•*"*-4 

B, 

50-100-50     lime     sulfur 

J        7        )        J        7 

1,2,3 

96 

68 

25 

4.0 

13 

Ba 

diluted  1  in  28  with 

1,  2,  3,  4 

140 

39 

15 

2.8 

15 

B3 

4-100  arsenate  of  lead 

1,  2,  3,  4,  5 

237 

45 

19 

4.0 

14 

B4 

1,  2,  3,  4,  5,  6 

140 

15 

15 

2.7 

7 

c, 

32-32-200         self-boiled 

*J         J         >         ?         J 

1,2,3 

438 

98 

38 

8.0 

8 

c, 

lime  and  sulfur  with 

1,  2,  3,  4 

323 

96 

16 

0.0 

10 

c, 

4-100  arsenate  of  lead 

1,  2,  3,  4,  5 

510 

98 

16 

2.0 

6 

C4 

1,  2,  3,  4,  5,  6 

660 

100 

29 

4.0 

19 

^4 

Commercial  lime  sulfur 

j.j     **j     LFJ      j-j     r^j     v* 

1,2,3 

343 

87 

26 

1.0 

10 

vt 

diluted   1  in  35  with 

1,  2,  3,  4 

160 

73 

32 

5.0 

8 

4-100  arsenate  of  lead 

1,  2,  3,  4,  5 

127 

55 

22 

0.0 

9 

D! 

1,  2,  3,  4,  5,  6 

203 

60 

35 

3.5 

10 

•*X4 

8-8-4-100   Bordeaux  ar- 

/          7           7           7           7 

1,2,3 

E! 

senate   of   lead1  

1,  2,  3,  4 

O-JJ 

E, 

>         ?        > 

1,  2,  3,  4,  5 

•"S 

E4 

J         J         J         ? 

1,  2,  3,  4,  5,  6 

4 

Check 

No  treatment  

J        7       7        7        7 

none 

210 

100 

100 

28.0 

20 

*A11  the  fruit  on  Plat  E  was  lost  by  freezing. 

was  exceptionally  large.  It  must  be  understood,  however,  that  the 
general  infection  that  year  could  not  have  been  worse,  for  the  check 
trees,  which  received  no  spray,  yielded  no  sound  fruit  and  lost  their 
foliage  early  in  September.  In  order  to  have  any  picked  fruit  for 
examination  from  the  unsprayed  trees,  it  was  necessary  to  gather  it 
three  or  four  weeks  before  the  fruit  on  the  sprayed  trees  was  ready 
to  harvest.  At  that  time  many  of  the  apples  were  rotting  on  the 
check  trees,  and  nearly  all  of  them  were  deformed  and  undersized. 
Much  of  the  injury  shown  in  the  russet  column  was  no  doubt  caused 
by  the  cold  weather.  An  examination  of  the  codling-moth  injuries 
shows  that  the  action  of  the  arsenate  of  lead  in  the  control  of  this 
insect  was  about  the  same  when  used  in  any  of  the  four  sprays. 

It  would  appear  from  these  data  that  none  of  the  lime-sulfur 
sprays  used  was  efficient  in  the  control  of  apple  scab  in  this  particu- 
lar season.  If  the  danger  of  spray  injury  could  be  eliminated,  any  of 


64  BULLETIN  No.  185  [February, 

the  cooked  solutions  might  prove  efficient  when  only  light  attacks  of 
scab  are  experienced.  Under  no  conditions  would  it  seem  wise  to  use 
self-boiled  lime  and  sulfur  for  diseases  of  the  apple. 

EFFICIENCY  OF  BORDEAUX  AND  MILK  OF  LIME  IN  REDUCING 
BORDEAUX  INJURY 

In  1905  the  Illinois  Agricultural  Experiment  Station  began  an  in- 
vestigation to  determine  the  cause  of  Bordeaux  injury,  and,  if  possi- 
ble, to  find  a  remedy  for  it.  Among  the  treatments  which  gave  the 
most  promise  of  reducing  this  injury  was  the  after-spray  with  milk 
of  lime ;  that  is,  the  following  of  the  regular  Bordeaux  application,  as 
soon  as  dry,  with  an  application  of  milk  of  lime.1 

In  order  to  determine  if  this  could  be  accomplished  on  a  commer- 
cial scale,  the  following  treatments  were  given  seven  plats,  arsenate 
of  lead  being  included  in  each,  4  pounds  to  each  100  gallons: 

Plat  11:  Milk  of  lime  alone.  This  treatment  was  given  in  lieu  of  the  regular 
sprayings  with  Bordeaux  in  order  to  determine  the  effect  of  lime  alone. 

Plat  12a:  Three  applications  of  6-6-100  Bordeaux,  each  followed  as  soon  as 
dry  by  8-100  milk  of  lime.  In  place  of  the  fourth  regular  spraying  with  Bor- 
deaux, milk  of  lime  was  substituted. 

Plat  12b:  The  same  applications  as  those  given  Plat  12a  with  one  additional 
application  of  Bordeaux  followed  with  milk  of  lime. 

Plats  13a  and  13b:  The  same  applications  as  those  given  Plats  12a  and  12b, 
respectively,  except  that  8-8-100  Bordeaux  was  used. 

Plat  14:  The  first  three  regular  applications  of  8-8-100  Bordeaux,  the  third 
followed  by  milk  of  lime. 

Plat  15:  The  first  three  regular  applications  of  8-8-100  Bordeaux. 

Plat  16 :  Four  applications  of  8-8-100  Bordeaux,  the  second,  third,  and  fourth 
applications  being  followed  with  8-100  milk  of  lime.  An  extra  application  of  8-100 
milk  of  lime  was  given  four  weeks  after  the  third  application  of  Bordeaux  and 
three  weeks  before  the  fourth. 

Plat  17 :  This  plat  received  the  first  three  regular  applications  of  6-6-100  Bor- 
deaux. 

EFFECT  ON  FOLIAGE 

Early  in  the  season  Plat  11  had  an  abundance  of  large  healthy 
leaves,  but  as  the  season  advanced  the  injuries  from  fungous  diseases 
and  from  insects  became  as  severe  as  upon  the  check  trees.  Plats  12 
and  13  were  in  excellent  condition  thruout  the  entire  season.  There 
was  no  foliage  injury  of  any  kind,  and  the  applications  of  lime  ma- 
terially increased  the  adhesiveness  of  the  Bordeaux.  There  was  no 
noticeable  difference  between  the  actions  of  8-8-100  and  6-6-100  Bor- 
deaux. 

Plats  14,  15,  and  17  suffered  so  severely  from  the  freeze  that  they 
never  fully  recovered  from  the  effects  of  it.  The  amounts  of  scab  and 

JC.  S.  Crandall,  111.  Agr.  Exp.  Sta.  Bui.  135,  p.  280,  1909. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


65 


insect  injury  were  quite  small  for  all  plats,  and  very  few  yellow 
leaves  appeared  on  any  of  them.  Plat  16  recovered  from  the  effects 
of  the  freeze  quite  rapidly.  The  trees  of  this  plat  were  well  coated 
with  the  spray  material  at  the  time  of  the  freeze,  and  since  adjoining 
trees  sprayed  only  with  Bordeaux  suffered  severely,  due  credit  must 
be  given  the  lime  for  the  part  it  played  in  shielding  them. 

EFFECT  ON  FRUIT 

On  those  trees  receiving  applications  of  lime  before  the  freeze, 
considerable  fruit  escaped  being  frozen.  The  examination  of  this 
fruit  gave  the  results  presented  in  Table  2. 

TABLE  2. — EFFECTS  OF  USING  MILK  OF  LIME  IMMEDIATELY  AFTER  APPLYING 

BORDEAUX  OF  VARYING  STRENGTHS  AND  BORDEAUX  WITHOUT 

MILK  OF  LIME,  IN  THE  EXPERIMENTS  AT  NEOGA,  1910 


Plat 

Treatment 

Applications 

• 
Q 

d'H. 
«& 

.2  ^3 

II 

«iH 

Cfc 

Percentage  of  picked 
apples  affected  by 

& 

8 

CO 

Curculio 

6C 

£% 

73  a 

o  a 

O 

3 

M 

12a 
12b 
13a 
13b 

16 
17 

6-6-4-100   Bordeaux  ar- 
senate  of  lead  

1,2,3 
1,  2,  3,  4 

1,  2,  3,  -,  5 
1,  2,  3,  4,  5 

1,2,3 
1,  2,  3,  4 

1,  2,  3,  -,  5 
1,  2,  3,  4,  5 

1,  2,  3,  -,  5 
2,  3,  4,  5 

1,2,3 

688 
530 
881 
249 

366 
94 

5.3 

5.2 
2.0 
0.0 

6.0 
5.2 

18.4 
16.7 
2.0 
3.0 

26.0 
30.8 

1.5 
4.5 
1.0 
0.7 

6.0 
6.3 

15.3 
15.2 
11.0 
6.7 

12.0 
25.5 

Milk  of  lime  used  

6-6-4-100   Bordeaux  ar- 
senate  of  lead  

Milk  of  lime  used  

8-8-4-100   Bordeaux  ar 
senate  of  lead  

Milk  of  lime  used  

8-8-4-100   Bordeaux  ar- 
senate  of  lead  

Milk  of  lime  used  

8-8-4-100   Bordeaux  ar- 
senate  of  lead  

Milk  of  lime  used  

6-6-4-100   Bordeaux  ar- 
senate  of  lead  

NOTE. — Plats  11,  14,  and  15  yielded  too  little  fruit  to  justify  comparison  with 
the  other  plats. 

It  will  be  seen  by  comparing,  under  the  column,  ' '  Total  no.  picked 
apples, ' '  the  plats  in  which  the  Bordeaux  was  followed  by  the  milk  of 
lime  and  Plat  17,  in  which  only  Bordeaux  was  used,  that  the  applica- 
tion of  milk  of  lime  had  a  decidedly  beneficial  effect  in  protecting  the 
apples  from  the  freeze.  There  is  also  no  doubt  that  the  after-spray 
of  milk  of  lime  prolongs  the  efficiency  of  the  Bordeaux  arsenate  of 


66 


BULLETIN  No.  185 


[February, 


lead  by  increasing  its  adhesiveness.  Altho  the  difference  in  the  per- 
centage of  scab  between  the  plats  sprayed  with  6-6-100  and  with 
8-8-100  Bordeaux,  as  used  in  Plats  12  and  13,  was  not  great,  there  was 
a  slight  advantage  in  favor  of  the  8-8-100  Bordeaux.  There  was  also 
a  slight  advantage  in  the  use  of  arsenate  of  lead  in  preventing 
curculio  and  codling-moth  injuries.  Moreover,  it  appeared  that  the 
after-spray  with  lime  had  a  tendency  to  reduce  the  amount  of  russet- 
ing,  as  in  all  plats  in  which  the  lime  was  used,  the  amount  of  russet 
was  considerably  less  than  where  the  Bordeaux  arsenate  of  lead  alone 
was  used.  However,  such  a  conclusion  based  upon  these  data  should 
be  considered  tentative,  since  much  of  the  russet  might  have  been 
due  to  the  cold  weather. 

CHEMICAL  ANALYSIS  OF  SOME  COMMERCIAL  BRANDS  OF 
ARSENATE  OF  LEAD 

Arsenate  of  lead  has  been  one  of  the  leading  insecticides  for  use 
in  combating  chewing  insects  for  a  number  of  years.  Within  the  last 
few  years,  commercial  manufacturers  have  made  and  offered  for  sale 
prepared  arsenates  of  lead,  about  which  many  requests  for  informa- 
tion have  been  received  at  this  station.  The  brands  which  were  found 
upon  the  market  in  this  state  in  January,  1910,  were  collected  and 
analyzed,  with  the  results  presented  in  Table  3. 

TABLE  3. — CHEMICAL  ANALYSES  OF  COMMERCIAL  ARSENATES  OF  LEAD 


Perc 

entages 

Brand 

A 

s  received 

Moisture 

free 

Moisture 

Lead 
oxid 

Arsenic 
oxid 

Lead 
oxid 

Arsenic 
oxid 

Soluble 
arsenic  oxid 

Sherwin-Williams.  . 
Grasselli  

48.18 
40.20 

35.77 
39.52 

12.76 
16.29 

69.02 
66.08 

24.62 
27.07 

All  less  than 
%  of  1 

Star  

40.20 

40.99 

16.95 

68.54 

28.34 

percent 

Niagara  

42.05 

38.42 

16.70 

66.29 

28.81 

Blanchard  

32.96 

43.05 

19.71 

64.21 

29.40 

Disparene  

51.08 

31.19 

14.97 

63.75 

30.60 

Swift  

45.56 

3553 

1704 

65.26 

31  31 

Hemingway  

39.05 

37.96 

19.15 

62.28 

31.41 

Bex  

46.41 

33.82 

17.13 

63.10 

31.96 

Target.  . 

4150 

3596 

1893 

61.46 

3235 

Eagle  

47.75 

34.12 

17.05 

65.30 

32.63 

Vreeland  

43.22 

35.53 

19.25 

62.57 

33.90 

Vreeland  powdered 

trace 

62.70 

33.76 

62.70 

33.76 

These  arsenates  of  lead  were  purchased  directly  from  the  manu- 
facturers, and  were  all  received  in  the  form  of  pastes,  with  the  excep- 
tion of  Vreeland  powdered.  An  examination  of  the  results  of  the 
analyses  shows  an  appreciable  variation  in  the  composition  of  the  dif- 
ferent samples,  the  percentage  of  arsenic  oxid  ranging  from  12.76  in 
Sherwin-Williams  to  19.71  in  Blanchard,  and  the  lead  oxid  from  31.19 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  67 

in  Disparene  to  43.05  in  Blanchard.  The  amount  of  soluble  arsenic 
oxid  is  shown  to  be  quite  low  in  all  samples.  Calculated  on  the  dry 
basis,  there  is  a  variation  in  arsenic  oxid  from  24.62  to  33.90  percent, 
and  in  lead  oxid  from  61.46  to  69.02  percent. 

Chemically  speaking,  there  are  a  number  of  different  arsenates  of 
lead,  but  there  are  only  two  which  are  used  commercially,1  the  tri- 
plumbic  arsenate,  represented  by  Pb3(As04)2  and  commonly  called 
neutral  or  ortho  arsenate  of  lead,  and  plumbic  hydrogen  arsenate  of 
lead,  represented  by  PbHAs04  and  commonly  called  acid  arsenate  of 
lead.  Most  of  the  above  samples  are  a  mixture  of  these  two ;  in  some 
the  neutral  predominates,  while  in  others  there  is  more  of  the  acid. 
Only  one,  Sherwin-Williams,  showed  the  arsenic  oxid  and  lead  oxid 
in  the  proportions  to  form  the  triplumbic  arsenate.  As  arsenic  is  the 
ingredient  in  arsenate  of  lead  which  gives  it  value  as  an  insecticide, 
the  above  analyses  show  that  the  manufacturers,  as  a  rule,  have  at- 
tempted to  put  out  products  containing  the  maximum  amount  of 
arsenic. 

In  order  to  obtain  reliable  data  upon  the  comparative  values  of 
the  different  arsenates  of  lead,  it  was  deemed  necessary  to  test  them  in 
the  field.  Since  it  was  impossible  to  try  all  of  these  which  were 
analyzed,  a  few  representative  ones,  based  on  analyses,  were  selected. 
These  were  tested  in  two  groups,  in  one  of  which  they  were  applied 
with  Bordeaux,  and  in  the  other  of  which  they  were  applied  with 
limo  sulfur. 

COMPARATIVE  VALUES  OF  VARIOUS  COMMERCIAL,  ARSENATES 
OF  LEAD  WITH  BORDEAUX 

The  following  arsenates  of  lead,  all  in  paste  form  with  the  excep- 
tion of  Vreeland  powdered,  were  applied  with  8-8-100  Bordeaux,  4  or 
6  pounds  being  used  to  each  100  gallons  as  indicated : 

Plat 

6 :     Sherwin-Williams    4-100 

7:     Sherwin-Williams    6-100 

10 :     Vreeland  powdered    4—100 

14:     Grasselli    4r-100 

20:     Grasselli    6-100 

21:     Lion     4-100 

22 :     Lion     , 6-100 

23 :     Vreeland   4-100 

24:     Vreeland   6-100 

25:     Hemingway 4—100 

26:     Hemingway 6-100 

27:     Star   4-100 

28:     Star   6-100 

29 :     Eagle 4-100 

30:     Eagle 6-100 


'U.  S.  Dept.  Agr.,  Bur.  of  Chem.,  Bui.  131,  p.  17. 


68 


BULLETIN  No.  185 


[February, 


Owing  to  a  delay  in  the  receipt  of  Hemingway  and  Sherwin-Wil- 
liams arsenates  of  lead,  Plats  6,  7,  25,  and  26  did  not  receive  the  first 
application ;  otherwise,  the  first  three  regular  applications  were  given 
to  all  plats.  These  plats  all  suffered  severely  from  the  freeze. 


EFFECT  ON  FOLIAGE 


Very  little  could  be  determined  from  the  foliage,  as  insect  in- 
juries were  practically  the  same  on  all  plats. 

EFFECT  ON  FRUIT 

On  a  number  of  plats  so  few  apples  survived  the  freeze  that  the 
fruit  was  not  worth  consideration.  Table  4  shows  the  records  which 
were  obtained  by  examining  apples  from  the  plats  bearing  fruit. 

TABLE  4. — EFFECTS  OF  VARIOUS  COMMERCIAL  ARSENATES  OF  LEAD  IN  COMBINATION 
WITH  BORDEAUX,  IN  THE  EXPERIMENTS  AT  NEOGA,  1910 


Plat 

Treatment 

Applications 

Total 
no. 
picked 
apples 

Percentage  of 
picked  apples 
affected  by 

Curculio 

Codling 
moth 

6 
7 
10 
20 
21 
22 
23 
Check 

4-100  Sherwin-Williams  arsenate  of  lead 
with  8  8-100  Bordeaux         

2,3 
2,3 
.1,  2,  3 
1,2,3 
1,2,3 
1,2,3 

1,2,3 
none 

694 

412 
152 
228 
204 
398 

345 
210 

35 
20 
36 
30 
52 
68 

60 
100 

7 
6 
8 
2 
8 
4 

18 

28 

6-100  Sherwin-Williams  arsenate  of  lead 
with  8-8-100  Bordeaux  

4-100  Vreeland  powdered  arsenate  of  lead 
with  8-8-100  Bordeaux  

6-100    Grasselli    arsenate    of    lead    with 
8-8-100  Bordeaux  

4-100  Lion  arsenate  of  lead  with  8-8-100 

6-100  Lion  arsenate  of  lead  with  8-8-100 

6-100    Vreeland    arsenate    of    lead   with 
8-8-100  Bordeaux  

No  treatment.  . 

Because  of  the  small  amounts  of  fruit  harvested  from  the  plats  of 
this  group,  no  definite  conclusions  are  justified.  However,  it  is  inter- 
esting to  note  that,  as  a  rule,  six  pounds  of  arsenate  of  lead  were  not 
any  more  efficient  in  preventing  injuries  from  the  codling  moth  and 
curculio  than  four  pounds.  It  is  also  evident  from  these  data  that  the 
first  application,  which  was  made  just  before  the  bloom,  had  no  influ- 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  69 

ence  upon  these  two  insects,  since  Plats  6  and  7,  which  did  not  re- 
ceive this  application,  showed,  from  a  practical  standpoint,  the  least 
amount  of  injury. 

COMPARATIVE  VALUES  OF  VARIOUS  COMMERCIAL  ARSENATES 
OF  LEAD  WITH  LIME  SULFUR 

When  arsenate  of  lead  is  added  to  lime-sulfur  solution,  a  chem- 
ical reaction  between  the  two  takes  place.  The  extent  and  nature  of 
this  reaction  differs  in  the  case  of  the  different  arsenates.1  In  order 
to  determine  whether  or  not  there  was  any  difference  in  the  action 
upon  the  trees  due  to  this  variation  in  reaction,  plats  were  treated  as 
shown  in  Table  5.  The  first  application  was  omitted,  owing  to  a  delay 
in  the  receipt  of  some  of  the  arsenates  of  lead. 

EFFECT  ON  FOLIAGE 

Considering  the  effects  on  the  foliage,  lime  sulfur  in  combination 
with  Sherwin-Williams  arsenate  of  lead,  as  used  on  Plat  1,  gave  the 
best  results.  This  mixture  was  the  most  adhesive,  permitted  the  least 
scab,  and  caused  very  little  foliage  injury.  The  arsenates  of  lead  used 
on  the  other  plats  acted  much  alike.  The  fourth  application  caused 
some  foliage  injury,  which  was  a  little  more  severe  upon  trees  re- 
ceiving lime  sulfur  and  Hemingway  and  Star  arsenates  of  lead  than 
upon  those  which  received  lime  sulfur  in  combination  with  the  Vree- 
land  brands.  Any  difference  in  insect  injury  to  the  foliage  was  too 
small  to  be  noticed. 

EFFECT  ON  FRUIT 

The  trees  in  these  plats  withstood  the  cold  fairly  well,  and  recov- 
ered quite  rapidly  from  all  apparent  injury.  On-  all  plats  some  fruit 
survived  the  freeze.  It  was  picked  and  examined  October  26,  with  the 
results  presented  in  Table  5. 

The  fruit  data  recorded  corroborate  the  notes  taken  on  the  foliage. 
They  show  that  fruit  from  those  trees  receiving  lime  sulfur  combined 
with  the  Sherwin-Williams  arsenate  of  lead  (Plat  1)  suffered  the 
least  from  scab,  curculio,  and  russet.  The  next  in  order  is  that  from 
trees  treated  with  the  Vreeland  brands,  between  which  there  is  little 
difference,  except  in  the  amount  of  scab.  In  the  prevention  of  scab,  the 
dry  arsenate  of  lead  in  combination  with  lime  sulfur  (Plat  4)  was 
somewhat  more  effective  than  the  paste  arsenate  of  lead  similarly  used. 
Neither  the  Star  nor  the  Hemingway  brand,  in  combination  with 
lime  sulfur,  exerted  much  influence  in  the  control  of  scab.  Of  these 
two  the  Star  brand  was  the  more  efficient  in  preventing  curculio  and 

JC.  E.  Bradley  and  H.  V.  Tartar,  Further  Studies  of  the  Eeactions  of  Lime- 
Sulfur  Solution  and  Alkali  Waters  on  Lead  Arsenates.  Jour.  Indus,  and  Eng. 
Chem.,  Vol.  2,  No.  7,  p.  328,  1910. 


70 


BULLETIN  No.  185 


[February, 


TABLE  5. — EFFECTS  OF  VARIOUS  COMMERCIAL  ARSENATES  OF  LEAD  IN  COMBINATION 
WITH  LIME  SULFUR,  IN  THE  EXPERIMENTS  AT  NEOGA,  1910 


Plat 

Treatment 

Applications 

o> 
5 

£  fr 

PI  ft 

rt  * 

3* 
•o  <o 

EH3 

°Qj 

Percentage  of 
picked  apples 
affected  by 

1 

GO 

Curculio 

bp 

.S* 

-3    -l^ 

rQ    O 
0    g 

0  S 

~» 

OQ 

02 

3 
PH 

1 
2 
3 
4 
5 
Check 

4-100  Sherwin-Williams  arsenate  of  lead 
with  lime  sulfur,  1—40  

2,3,4 
2,3,4 
2,3,4 
2,3,4 

2,3,4 
none 

267 
318 
1225 
489 

337 
210 

58 
98 
100 
83 

68 
100 

19 
54 
27 
31 

30 
100 

6 
14 
3 
4 

6 

28 

6 
46 
36 
22 

24 
?,0 

4-100  Hemingway  arsenate  of  lead  with 
lime  sulfur    1—40  

4-100  Star  arsenate  of  lead  with  lime 
sulfur,  1-40   

4-100    Vreeland   dry   arsenate    of   lead 
with  lime  sulfur,  1—40  

4-100    Vreeland   arsenate    of    lead   with 
lime  sulfur,  1—40  

No  treatment  . 

codling-moth  injuries.  Both  caused  considerable  russet,  tho  the  ap- 
ples sprayed  with  the  Hemingway  brand  showed  more  russet  than 
those  receiving  the  Star  brand.  Since  the  treatment  given  these  plats 
was  identical  except  in  the  brand  of  arsenate  of  lead  used,  the  varia- 
tion in  the  results  must  be  due,  in  part  at  least,  to  differences  in  the 
reactions  resulting  when  the  different  arsenates  of  lead  were  mixed 
with  the  lime-sulfur  solution. 

From  these  results  we  must  conclude  that,  for  the  summer  spray- 
ing of  apples,  the  neutral  arsenate  of  lead  (to  which  class  the  Sher- 
win-Williams appears  to  belong)  in  combination  with  lime-sulfur 
solution  produces  a  spray  which  is  more  efficient  and  safer  to  use  than 
one  made  by  combining  lime  sulfur  with  arsenates  of  lead  containing 
higher  percentages  of  arsenic,  which  are  known  as  acid  arsenates  of 
lead.1 

SUMMARY  OF  EESULTS  AT  NEOGA,  1910 

1.  Bordeaux,  made  from  8  pounds  of  copper  sulfate,  8  pounds  of 
lime,  and  100  gallons  of  water,  was  a  more  efficient  fungicide  for  use 
upon  apples  than  any  of  the  lime-sulfur  sprays  used. 

2.  A  concentrated  lime-sulfur  solution  equivalent  in  efficiency  to 
commercial  solutions  can  be  made  and  stored  by  the  grower.    There 
was  no  deterioration  of  the  homemade  concentrated  lime  sulfur  on 
standing. 

JSee  footnote  on  following  page. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  71 

3.  Self-boiled  lime  and  sulfur  was  easily  washed  off  and  pos- 
sessed very  little  f  ungicidal  value  in  the  control  of  apple  scab. 

4.  Injuries  to  foliage  and  fruit  following  the  use  of  Bordeaux 
were  lessened  by  following  the  applications  of  Bordeaux,  as  soon  as 
dry,  with  8-100  milk  of  lime. 

5.  Applications  of  milk  of  lime  had  a  stimulating  effect  upon  the 
foliage  and  shielded  the  fruit  from  the  freeze  of  April  23. 

6.  With  a  lime-sulfur  solution,  neutral  or  ortho  arsenate  of  lead 
gave  better  results  than  arsenates  of  lead  containing  higher  percent- 
ages of  arsenic  oxid.1 


1The  following  extract  from  an  article  by  W.  H.  Volek,  ' '  The  Significance  of 
Lead  Arsenate  Composition,"  published  in  Science  N.S.  Vol.  33,  No.  857,  pp.  866- 
870,  June  2,  1911,  has  a  bearing  upon  this  point :  ' '  The  acid  arsenates  are  stable 
under  acid  conditions,  but  are  transposed  into  the  ortho -arsenate,  the  most  stable 
compound,  under  neutral  and  alkaline  conditions.  The  transposition  involves  the 
liberation  of  arsenic  oxid  or  soluble  arsenates.  The  significance  is  at  once  appar- 
ent. When  arsenate  of  lead  is  applied  as  a  spray  it  is  subjected  to  neutral  and 
alkaline  conditions.  This  is  especially  true  if  the  water  used  in  spraying  contains 
alkalies.  That  is,  the  conditions  favorable  to  the  transpositions  of  the  acid  arsen- 
ates into  the  ortho-compound  obtain.  As  fast  as  the  neutral  waters  of  fogs,  and 
rains  wash  away  the  liberated  arsenic  oxid,  or  when  the  latter  is  absorbed  by  the 
plant  tissues  themselves,  the  conditions  are  restored  for  more  to  be  formed.  The 
ultimate  result  is  the  complete  transposition  of  the  acid  arsenates  to  the  ortho- 
compound  and  the  liberation  of  the  excess  arsenic  oxid. ' ' 


72  BULLETIN  No.  185  [February, 


SPRAYING  EXPERIMENTS  IN  1911  AT  NEOGA, 
CUMBERLAND   COUNTY 

BY  O.  S.  WATKINS 

OBJECTS 

During  the  summer  of  1911  spraying  experiments  were  again  car- 
ried on  at  Neoga  along  lines  of  investigation  similar  to  those  of  1910. 
Tests  were  made  to  ascertain  the  efficiency  of  (1)  lime  sulfur  and 
Bordeaux;  (2)  the  substitution  of  lime  sulfur  for  Bordeaux  in  one  or 
two  of  the  first  three  regular  summer  applications;  (3)  drenching  ap- 
plications of  Bordeaux  and  the  use  of  milk  of  lime  in  reducing  Bor- 
deaux in  jury;  (4)  lime  sulfur  used  at  various  strengths ;  (5)  commer- 
cial arsenates  of  lead  used  with  (a)  Bordeaux  and  (b)  lime  sulfur; 
(6)  the  use  of  lime  sulfur  arsenate  of  lead  and  copper  sulfate  mixed 
and  of  certain  new  fungicides,  including  Cucasa,  Sulfocide,  and  cop- 
per ferrocyanide. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

The  same  orchard  at  Neoga  was  again  chosen  for  carrying  on  the 
experiments,  and  the  same  block  of  trees  was  used  as  in  1910.  As 
before,  the  orchard  was  divided  into  plats  of  four  to  six  trees  each 
and  the  various  plats  were  sprayed  differently.  Check  trees  were  left 
with  which  to  compare  the  sprayed  trees. 

APPARATUS  AND   MATERIALS 

The  method  of  preparing  the  spray  mixtures  and  the  manner  of 
applying  them  were  the  same  as  described  for  1910. 

CHARACTER  OF  RECORDS  AND  METHOD  OF  MAKING 

The  character  of  the  records  and  the  method  of  making  them  were 
the  same  as  in  1910.  See  page  60. 

WEATHER   CONDITIONS 

The  conditions  of  1911  were  abnormal  as  regards  rainfall.  The 
summer  was  exceptionally  dry,  very  little  rain  falling  between  the 
middle  of  June  and  the  first  of  September,  while  both  September  and 
October  were  wet  months.  The  trees  came  into  bloom  early  in  May, 
and  during  most  of  the  blooming  period  there  was  a  cold  rain  which 
continued  for  several  days.  Unfavorable  as  these  conditions  were  for 
pollination,  there  was  a  good  set  of  fruit.  The  injury  caused  by  in- 
sects was  very  slight,  and  the  only  serious  infection  of  scab  came  dur- 
ing the  blooming  period.  The  foliage  and  fruit  on  neighboring  un- 
sprayed  orchards  did  not  fall  prematurely,  as  was  the  case  in  1910, 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


73 


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and  at  the  close  of  the  season  the  check  trees  in  the  experimental 
orchard  were  as  healthy  in  appearance  as  the  sprayed  trees. 

SPRAY  DATES 

A  winter  application  of  lime  sulfur  was  given  the  entire  orchard 
about  the  middle  of  April ;  and  from  one  to  five  summer  applications 
were  made  upon  or  near  the  following  dates :  April  20,  May  18,  June 
3,  June  25,  August  15. 

RELATIVE  EFFICIENCY  OF  LIME  SULFUR  AND  BORDEAUX 

During  the  last  few  years  lime  sulfur  has  been  attracting  atten- 
tion as  a  fungicide  for  the  summer  treatment  of  apples.  In  order  to 
determine  the  adaptability  of  this  spray  for  Illinois  orchards,  the  fol- 
lowing experiment  was  carried  out : 

Plats  A,  B,  and  C,  consisting  of  sixteen  trees  each,  were  subdivided 
into  plats  of  four  trees  each.  It  was  the  original  intention  to  give 
Aj,  B17  and  Clt  three  applications ;  A2,  B2,  and  C2,  four  applications ; 
A3,  B3,  and  C3,  five  applications ;  and  A4,  B4,  and  C4,  six  applications 
as  in  1910.  The  plan  was  changed,  however,  so  that  Plats  A1;  A2,  B1; 
B2,-  Cj,  and  C2  each  received  three  applications ;  A3,  B3,  and  C3,  four 
applications ;  and  A4,  B4,  and  C4,  five  applications,  as  shown  in  Table  6. 

From  the  experiments  in  1910  it  was  learned  that  self-boiled  lime 
and  sulfur  would  not  control  apple  scab,  and  also  that  the  home-con- 
centrated solution  was  as  efficient  as  the  ordinary  homemade  spray ;  it 
was  deemed  unnecessary,  therefore,  to  repeat  these  treatments  in  1911. 

EFFECT  ON  FOLIAGE 

The  only  noticeable  infection  of  scab  came  before  many  of  the 
leaves  were  out,  and  as  the  amount  was  small  in  all  cases,  it  was  im- 
possible to  detect  any  difference  in  this  respect  between  the  three 
plats.  This  lack  of  scab  no  doubt  reduced  the  amount  of  foliage  in- 
jury caused  by  the  spray,  as  infected  leaves  are  the  first  to  turn 
brown  when  spray  is  applied.1  At  no  time  during  the  season  did  any 
yellow  leaves  appear  upon  the  trees  sprayed  with  Bordeaux.  The  first 
two  applications  of  lime  sulfur  to  Plats  A  and  B  caused  no  injury 
.whatever,  and  the  amount  following  the  third  application  was  very 
small.  The  fourth  application  burned  about  30  percent  of  the  leaves 
at  the  tips  and  along  the  edges,  and  the  fifth  application  affected  about 
50  percent  in  the  same  way.  The  injury  was  more  severe  in  Plat  B, 
upon  which  the  commercial  lime  sulfur  had  been  used,  than  upon  Plat 
A,  which  had  received  the  home-concentrated  solution ;  but  in  each  case 
the  trees  rapidly  recovered.  The  adhesiveness  of  the  Bordeaux  was 
much  better  than  that  of  either  of  the  lime-sulfur  sprays,  and  the 
amount  of  spray  injury  caused  by  it  was  negligible. 

'C.  S.  Crandall,  111.  Agr.  Exp.  Sta.  Bui.  135,  p.  225,  1909. 


1&16]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  75 

EFFECT  ON  FRUIT 

The  fruit  in  these  plats  was  picked  and  examined  October  16  and 
17,  with  the  results  presented  in  Table  6.  This  table  shows  the  rela- 
tive efficiency  of  lime  sulfur  and  Bordeaux  on  these  plats  and  the 
value  of  three,  four,  and  five  applications.  Since  the  object  of  the 
experiment  was  to  determine  the  comparative  value  of  the  different 
mixtures  for  the  prevention  of  apple  scab,  special  attention  should  be 
given  to  the  scab  column.  The  Bordeaux  used  on  Plat  C  gave  the 
best  result,  while  the  commercial  lime  sulfur  as  used  on  Plat  B  gave 
somewhat  better  results  than  the  home-concentrated  solution  used  on 
Plat  A.  The  fifth  application  with  commercial  lime  sulfur  appears  to 
have  been  of  no  value.  There  was  very  little  russeting  of  fruit,  partly, 
perhaps,  because  of  the  fact  that  there  was  so  little  harm  done  by 
insects  and  fungous  diseases.1 

The  burn  recorded  in  the  last  column  was  caused  by  lime  sulfur 
arsenate  of  lead,  and  upon  specimens  affected  was  quite  serious.  The 
third  application  of  spray,  made  about  the  first  of  June,  was  respon- 
sible for  most  of  the  injury.  The  burn  appeared  as  dark  brown, 
sunken  areas,  usually  circular  in  shape,  in  which  the  tissue  was  tough 
and  leathery,  making  the  injury  readily  distinguishable  from  ordinary 
sunscald.  After  it  first  appeared  it  developed  very  rapidly,  sometimes 
affecting  almost  the  whole  fruit.  As  the  apples  increased  in  size,  the 
burned  part  had  a  tendency  to  split  away;  it  sometimes  sloughed 
off  entirely.  In  such  cases  a  russeted  scar  remained,  which  somewhat 
healed  over  as  the  season  advanced.  The  injury  was  more  severe  upon 
trees  sprayed  with  commercial  lime  sulfur  than  upon  those  receiving 
the  home-concentrated  solution.  This  burn  was  unlike  anything 
previously  reported.  It  differed  from  lime-sulfur  injury  on  foliage, 
which  always  appears  very  shortly  after  application  of  the  spray,  in 
that  it  was  not  apparent  until  about  ten  days  after  any  application 
had  been  made.  Between  the  time  of  application  and  the  first  appear- 
ance of  the  injury,  there  intervened  several  very  hot  days.  There  was 
only  a  trace  of  rain  in  that  time,  but  upon  several  mornings  there 
were  excessively  heavy  dews. 

The  grade  columns  in  Table  6  are  noteworthy  in  that  they  show 
the  percentage  of  No.  1  apples  in  the  C  plats  (sprayed  with  Bor- 
deaux arsenate  of  lead)  to  be  considerably  greater  than  in  either  of 
the  other  plats.  Those  picked  from  the  check  trees  were  exception- 
ally good  for  unsprayed  apples  and  were  harvested  at  the  regular 
time.  This  was  rather  unexpected,  as  usually  by  picking  time  most 
of  the  fruit  in  untreated  plats  either  has  fallen  or  has  rotted  on  the 
trees. 

A  noticeable  fact  not  shown  in  the  table  was  the  variation  in  color 
between  the  fruit  harvested  from  the  different  plats.  The  apples 

1The  author  believes  that  foliage  injured  by  insects  or  fungi  is  more  readily 
injured  by  sprays  than  is  healthy  foliage. 


76 


BULLETIN  No.  185 


[February, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  77 

which  were  sprayed  with  Bordeaux  arsenate  of  lead  were  much  better 
colored  than  those  which  received  lime  sulfur  arsenate  of  lead  sprays. 

SUBSTITUTION  OF  LIME  SULFUR  FOR  BORDEAUX  IN  ONE  OR  Two  OF  THE 
FIRST  THREE  REGULAR  SUMMER  APPLICATIONS 

The  experiments  thus  far  considered  appear  to  show  that  Bordeaux 
for  use  as  a  fungicide  upon  apples  is  superior  to  any  of  the  lime-sulfur 
sprays.  However,  since  applications  of  Bordeaux  are  occasionally 
followed  by  a  russeting  of  the  fruit  and  a  premature  defoliation,  it 
cannot  be  considered  an  ideal  spray.  Lime  sulfur  has  been  shown  to 
possess  certain  fungicidal  properties,  but  it  has  the  great  disad- 
vantage, aside  from  possible  injurious  effects,  of  lack  of  adhesiveness. 
In  order  to  see  if  it  would  be  possible  to  substitute  lime  sulfur  for 
one  or  more  of  the  regular  applications  of  Bordeaux,  applications 
were  made  as  shown  in  Table  7. 

EFFECT  ON  FOLIAGE 

Very  little  information  could  be  gained  from  the  foliage  notes,  as 
the  amount  of  injury  of  all  kinds  was  small  on  all  plats.  Immediately 
after  the  third  application  of  lime  sulfur  arsenate  of  lead  had  been 
made,  June  3,  the  trees  receiving  it  showed  some  foliage  injury,  but 
not  enough  to  be  considered  important.  Ten  days  later,  however,  a 
very  serious  burning  of  the  fruit  developed. 

EFFECT  ON  FRUIT 

The  fruit  on  these  plats  was  picked  and  examined  on  October  17, 
with  the  results  presented  in  Table  7.  These  data  show  that  the  most 
satisfactory  results  were  secured  when  Bordeaux  was  used  for  the 
first  and  third  applications  and  lime  sulfur  for  the  second  (Plat  24). 
Under  this  treatment  there  was  a  very  low  percentage  of  scab  and 
no  spray  injury  of  any  kind ;  and  only  one  percent  of  the  apples  were 
culls.  The  fruit  on  Plat  22,  which  received  the  first  and  second  appli- 
cations of  lime  sulfur  and  the  third  of  Bordeaux,  was  very  good, 
and  differed  only  slightly  from  that  picked  from  Plat  24. 

EFFICIENCY  OF  BORDEAUX  USED  IN  DIFFERENT  WAYS  IN  REDUCING 

BORDEAUX  INJURY 

It  has  been  the  experience  of  some  growers  who  are  in  the  habit 
of  drenching  their  trees  when  spraying  with  Bordeaux  that  very  little 
of  the  fruit  russeted.  In  order  to  secure  data  on  this  point,  a  test 
was  made  to  determine  the  difference  in  the  amount  of  russet  caused 
by  drenching  and  by  light  but  thoro  applications.  Investigations1 
have  shown  that  the  most  severe  russeting  of  fruit  caused  by  Bordeaux 
is  the  result  of  the  applications  being  made  shortly  after  the  fall  of 

»U.  P.  Hedrick,  N.  Y.  (Geneva)  Agr.  Exp.  Sta.  Bui.  287,  p.  163. 


78 


BULLETIN  No.  185 


[February, 


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Lime  sulfur  arsenate  of  lead 
Bordeaux  arsenate  of  lead  

Lime  sulfur  arsenate  of  lead  .  .  . 
Bordeaux  arsenate  of  lead  

Bordeaux  arsenate  of  lead  
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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  79 

the  petals.  In  continuing  the  treatments  of  1910  made  in  order  to 
determine  the  best  method  of  reducing  the  injury  following  the  use 
of  Bordeaux,  four  plats  were  treated  as  shown  in  Table  8. 

EFFECT  ON  FOLIAGE 

The  fungous  and  insect  injuries  to  the  foliage  were  so  slight  in 
all  plats  that  no  differences  could  be  distinguished.  The  drenching 
applications  made  on  Plat  34  were  much  more  adhesive  than  the  regu- 
lar applications  made  on  Plat  35  and  seemed  to  exert  a  stimulating 
action.  The  foliage  in  Plat  34  was  unusually  large  and  vigorous,  and 
of  a  very  dark  green  color.  No  yellow-leaf  appeared  on  that  plat, 
and  only  about  5  percent  of  the  leaves  on  Plat  35  were  so  affected. 
There  was  no  noticeable  difference  resulting  from  the  treatments  given 
Plats  36  and  37,  the  general  appearance  of  both  being  the  same  thru- 
out  the  entire  season.  No  yellow-leaf  appeared  at  any  time  upon 
either  plat. 

EFFECT  ON  FRUIT 

The  fruit  from  the  trees  in  Plats  34,  35,  36,  and  37  was  picked 
and  examined  October  17.  The  results,  presented  in  Table  8,  show 
that  the  heavy  application  of  Bordeaux  arsenate  of  lead  was  much 
preferable  to  the  usual  lighter  application.  The  efficiency  of  the 
mixture  was  not  only  greater  in  controlling  scab,  but  the  amount  of 
russeting,  for  which  the  spray  was  no  doubt  responsible,  was  much 
less.  The  results  from  Plats  36  and  37  seem  to  indicate  that  it  matters 
very  little  whether  the  lime  follows  the  second  or  the  third  applica- 
tion. The  apples  in  Plat  37  graded  slightly  better  than  those  in  Plat 
36.  Since  these  results  are  not  entirely  in  accord  with  those  ob- 
tained in  1910,  the  subject  needs  further  investigation. 

LIME  SULFUR  USED  AT  VARIOUS  STRENGTHS 

In  the  preceding  experiments  where  lime  sulfur  was  used,  the  solu- 
tion in  all  cases  contained  8  pounds  of  sulfur  in  solution  in  each  100 
gallons  of  spray.  In  order  to  determine  the  efficiency  and  safety 
of  lime-sulfur  solutions  of  various  strengths,  plats  were  sprayed  with 
commercial  lime  sulfur  as  shown  in  Table  9. 

EFFECT  ON  FOLIAGE 

Very  little  difference  was  noted  in  the  foliage  in  the  various  plats. 
In  each  case  there  was  a  slight  injury  following  the  third  application, 
but  in  no  plat  did  it  prove  permanent. 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  81 

EFFECT  ON  FRUIT 

The  records  of  the  fruit,  which  was  picked  and  examined  October 
13,  are  presented  in  Table  9.  The  weakest  solution  used,  one  gallon  of 
concentrated  solution  to  50  gallons  of  water,  a  spray  containing  about 
21/2  pounds  of  sulfur  per  50  gallons,  seemed  to  be  the  proper  dilution 
for  scab  under  conditions  as  they  existed  during  1911.  In  this  plat 
there  were  not  only  fewer  scabby  apples,  but  a  larger  percentage  of 
No.  1  apples  than  is  credited  to  any  other  plat.  A  noticeable  feature 
was  the  small  amount  of  injury  resulting  from  the  strong  solution 
used  on  Plat  44.  There  were  in  each  100  gallons  of  spray  used  on  this 
plat  about  16  pounds  of  sulfur,  which  is  twice  the  amount  generally 
considered  safe  for  use  upon  apples.  In  order  to  determine  the  effect 
of  these  dilutions  in  seasons  of  more  abundant  rainfall,  further  inves- 
tigations are  necessary. 

COMMERCIAL  ARSENATES  OF  LEAD  WITH  BORDEAUX 

In  1911  various  commercial  arsenates  of  lead  were  tested  in  com- 
bination with  Bordeaux,  as  shown  in  Table  10. 

EFFECT   ON  FOLIAGE 

Very  little  could  be  learned  from  examination  of  the  foliage  as  the 
amount  of  insect  injury  to  the  leaves  was  unimportant.  There  were 
no  noticeable  differences  in  the  adhesiveness  of  the  mixtures. 

EFFECT  ON  FRUIT 

Table  10  presents  the  results  of  the  examination  of  fruit. 

As  in  1910,  very  little  can  be  determined  from  the  results  obtained, 
since  the  variation  between  the  different  plats  was  only  7  percent  in 
curculio  injury,  and  but  3  percent  in  codling-moth  injury.  The  varia- 
tion in  the  percentage  of  russeting  may  be  due  in  part  to  the  brand 
of  arsenate  of  lead  which  was  used,  as  other  conditions  were  the  same. 

COMMERCIAL  ARSENATES  OF  LEAD  WITH  LIME  SULFUR 

As  a  further  test  of  the  action  of  the  various  arsenates  of  lead 
when  applied  in  combination  with  lime  sulfur,  various  brands  were 
added  to  commercial  lime  sulfur  and  tested  as  shown  in  Table  11. 

EFFECT  ON  FOLIAGE 

There  was  some  foliage  injury  on  all  plats  from  time  to  time  thru- 
out  the  summer,  but  only  in  Plat  5,  which  received  Grasselli  arsenate 
of  lead  alone,  was  it  of  a  permanent  nature.  Here  there  was  very 
little  injury  until  about  the  middle  of  September,  when  the  leaves 


82 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  83 

turned  brown  along  the  edges  and  at  the  tips.  They  retained  this 
appearance  thruout  the  remainder  of  the  season,  and  about  25  percent 
of  the  foliage  fell  prematurely.  The  materials  used  on  Plats  7,  8,  and 
9  were  slightly  more  adhesive  than  those  used  on  the  other  plats. 

EFFECT  ON  FRUIT 

These  plats  all  had  an  abundance  of  fruit,  which  was  picked  Octo- 
ber 24  and  25,  and  examined  with  the  results  shown  in  Table  11. 

The  most  noticeable  feature  of  this  table  is  the  variation  in  the 
amount  of  scab.  Plats  7,  6,  and  3,  which  were  sprayed  with  Sherwin- 
Williams,  Swift,  and  Vreeland  arsenates  of  lead,  respectively,  were 
least  infected  with  scab,  having  16,  18,  and  19  percent  of  scabby 
apples.  Owing  to  the  small  amount  of  insect  injury,  little  can  be 
said  as  to  the  comparative  insecticidal  value  of  the  different  brands 
of  arsenates  of  lead  used.  There  was  a  varying  amount  of  russet  and 
burn  credited  to  the  different  plats,  but  the  difference  was  not  great. 
However,  since  neither  arsenate  of  lead  nor  lime  sulfur,  when  used 
alone,  caused  any  burning,  this  injury  appeared  to  be  due  to  the  re- 
action resulting  when  the  two  are  combined. 

Attention  is  called  especially  to  the  records  obtained  from  Plat  5, 
which  received  arsenate  of  lead  alone,  and  Plat  10,  which  received 
lime  sulfur  alone.  It  will  be  seen  from  these  results  that  both  lime 
sulfur  and  arsenate  of  lead  when  used  alone  possess  some  fungicidal 
value,  but  that  when  combined  they  produce  a  much  more  efficient 
spray.  Attention  is  also  directed  to  the  large  amount  of  codling-moth 
injury  recorded  against  Plat  10  as  compared  with  the  check  plat,  sug- 
gesting a  possible  attraction  of  the  codling-moth  adults  to  trees 
sprayed  with  lime  sulfur.  In  fact,  the  fruit  in  this  plat  suffered 
worse  from  codling  moth  than  any  of  the  check  trees  thruout  the  en- 
tire orchard. 

Altho  the  results  recorded  in  the  different  columns  do  not  show 
wide  variation  among  the  different  plats,  they  are  in  accord  with 
those  obtained  in  1910,  which  showed  that,  in  combination  with  lime- 
sulfur  solution,  the  neutral  arsenate  of  lead  produced  a  spray  which 
was  more  efficient  and  safer  to  use  than  those  arsenates  of  lead  higher 
in  arsenic  oxid. 

CERTAIN  NEW  FUNGICIDES  AND  INSECTICIDES 

In  order  to  test  the  value  of  lime  sulfur  arsenate  of  lead  when 
mixed  with  copper  sulfate  and  also  the  value  of  certain  new  fungi- 
cides, various  homemade  and  proprietary  mixtures  were  applied  as 
shown  in  Table  12. 

EFFECT  ON  FOLIAGE 

All  mixtures  of  lime  sulfur  arsenate  of  lead  and  copper  sulfate 
showed  quite  plainly  upon  the  trees,  and  varied  in  color  from  dark 


84 


BULLETIN  No.  185 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  85 

brown  to  almost  black.  Plats  18  and  19  looked  very  much  alike;  on 
Plat  17  the  spray  showed  a  somewhat  darker  brown,  and  on  Plat  20 
almost  black.  Permanent  injury  from  these  sprays  was  negligible, 
altho  for  several  days  after  the  application  to  Plat  20  had  been  made, 
its  foliage  presented  a  scorched  appearance.  This,  however,  soon  dis- 
appeared, and  thruout  the  remainder  of  the  season  the  trees  appeared 
very  healthy.  There  was  an  abundance  of  foliage  of  good  size  and  of 
a  dark  green  color  on  all  these  plats.  The  mixtures  applied  were  all 
of  about  equal  adhesiveness  and  remained  visible  thru  most  of  the 
summer. 

Cucasa,  when  dried  upon  the  trees,  resembled  Bordeaux  but  did 
not  prove  quite  so  adhesive.  There  was  some  foliage  injury  at  differ- 
ent times  during  the  summer  on  the  trees  sprayed  with  this  mixture, 
and  about  20  percent  of  the  leaves  turned  yellow  and  fell.  The  ma- 
terial used  was  some  that  was  carried  over  from  1910,  and  might  have 
been  less  satisfactory  than  the  fresh  product. 

Copper  ferrocyanide  is  a  new  spray  of  considerable  promise  made 
from  copper  sulfate  and  potassium  ferrocyanide.  The  two  salts  were 
dissolved  separately,  and  when  poured  together  produced  a  flocculent 
red  precipitate  of  copper  ferrocyanide.  This  mixture  gave  a  red  cast 
to  the  leaves  which  was  plainly  visible.  The  foliage  was  quite  dense, 
of  good  size,  much  darker  green,  and  glossier  than  that  on  any  other 
plat  in  the  orchard.  No  injury  of  any  kind  was  noticed  at  any  time 
during  the  season.  It  is  thought  that  this  mixture  possesses  both  in- 
secticidal  and  fungicidal  value,  but  owing  to  the  scarcity  of  insect 
pests  and  fungous  diseases,  as  well  as  conditions  conducive  to  foliage 
injury,  the  results  obtained  this  year  were  rather  indefinite.  The 
cost  of  the  material  at  the  strength  used  is  about  one-third  that  of 
lime  sulfur  arsenate  of  lead. 

EFFECT  ON  FRUIT 

The  recorded  data  show  that  of  the  four  sprays  used  on  Plats  17,  18, 
19,  and  20,  made  by  combining  lime  sulfur  arsenate  of  lead  and  vary- 
ing amounts  of  copper  sulfate,  those  used  on  Plats  17  and  19  con- 
trolled scab  exceptionally  well.  The  spray  injury  as  shown  by  the  rus- 
set and  burn  columns  was  negligible.  The  grading  was  fairly  good 
for  all  plats.  The  results  seem  to  indicate  that  the  mixtures  made 
from  lime  sulfur  arsenate  of  lead  with  4  pounds  of  copper  sulfate 
and  with  the  Bordeaux  arsenate  of  lead,  as  used  on  Plats  17  and  19, 
respectively,  are  probably  the  best  combinations.  Lime  sulfur  arsenate 
of  lead  with  2  pounds  of  copper  sulfate  was  too  weak  to  control  the 
fungous  diseases  properly,  and  when  made  with  6  pounds  of  copper 
sulfate  produced  a  very  bulky  precipitate  which  prevented  a  thoro 
coating  of  all  parts  of  the  fruit  and  foliage. 

The  fungicidal  value  of  Cucasa  was  almost  equal  to  that  of  Bor- 
dfaux;  no  russeting  of  the  fruit  followed  its  use.  -Copper  ferro- 


86 


BULLETIN  No.  185 


[February, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  87 

cyanide,  the  material  applied  to  Plat  28,  was  used  sparingly,  as  noth- 
ing was  known  regarding  its  action  upon  the  foliage  and  fruit.  These 
were  the  first  data  obtained  by  the  station  from  fruit  sprayed  with 
this  mixture  and  were  very  encouraging.  The  apples  picked  from 
this  plat  were  colored  perfectly  and  had  an  unusually  polished  finish. 
While  most  of  these  new  sprays  gave  promising  results,  no  recom- 
mendations can  be  made  until  they  have  been  further  tested. 

SUMMARY  OP  RESULTS  AT  NEOGA,  1911 

1.  Bordeaux  made  from  8  pounds  of  copper  sulfate,  8  pounds  of 
lime,  and  100  gallons  of  water  was  more  efficient  than  any  of  the 
lime-sulfur  sprays  used. 

2.  Applications  of  lime  sulfur  in  combination  with  arsenate  of 
lead,  made  later  than  two  or  three  weeks  after  the  fall  of  the  petals, 
caused  serious  injury  to  the  fruit. 

3.  The  most  satisfactory  treatment  for  apples  consisted  of  (1) 
8-8-4-100  Bordeaux  arsenate  of  lead  for  the  application  immediately 
preceding  the  bloom;  (2)  lime-sulfur  solution,  100  gallons  of  which 
contained  8  pounds  of  sulfur,  in  combination  with  4  pounds  of  arsen- 
ate of  lead,  for  the  application  immediately  after  the  fall  of  the 
petals;  and  (3)  8-8-4-100  Bordeaux  arsenate  of  lead  for  the  applica- 
tion made  about  ten  days  after  the  fall  of  the  petals. 

4.  Injuries  to  foliage  and  fruit  following  the  use  of  Bordeaux 
were  lessened  by:  (1)  following  the  applications  of  Bordeaux,  as  soon 
as  dry,  with  8-100  milk  of  lime;  and  (2)  using  the  "drench"  spray  of 
Bordeaux. 

5.  A  solution  of  lime  sulfur  containing  5  pounds  of  sulfur  in  each 
100  gallons,  and  combined  with  arsenate  of  lead,  prevented  scab  bet- 
ter than  stronger  solutions. 

6.  For  use  with  a  lime-sulfur  solution,  an  arsenate  of  lead  high 
in  lead  oxid  gave  better  results  than  arsenates  containing  high  per- 
centages of  arsenic  oxid. 

7.  A  mixture  of  lime-sulfur  solution  and  arsenate  of  lead  was 
more  efficient  in  preventing  apple  scab  than  lime  sulfur  used  alone. 

8.  Arsenate  of  lead  when  used  alone  exercised  some  fungicidal 
action,  but  caused  considerable  foliage  injury. 

9.  Lime  sulfur  arsenate  of  lead  in  combination  with  copper  sul- 
fate gave  an  efficient  spray  and  caused  no  injury  to  either  fruit  or 
foliage. 

10.  Sulfocide  in  combination  with  Paris  green  caused  very  seri- 
ous foliage  injury. 

11.  Cucasa  proved  almost  as  efficient  as  Bordeaux  in  preventing 
infection  of  scab ;  it  caused  no  russeting  of  the  fruit,  but  decidedly 
injured  the  foliage. 

12.  Copper  ferrocyanide,  made  from  copper  sulfate  and  potassium 
ferrocyanide,  controlled  scab  and  insects  very  efficiently. 


88  BULLETIN  No.  185  [February, 


SPRAYING  EXPERIMENTS  IN  1912  AT  NEOGA, 
CUMBERLAND  COUNTY 

By  O.  8.  WATKINS 


OBJECTS 

Neoga  was  again  chosen  in  1912  for  carrying  on  spraying  experi- 
ments, the  chief  lines  of  investigation  being  tests  to  gain  further  in- 
formation upon:  (1)  the  fungicidal  value  of  winter  applications  of 
lime  sulfur;  (2)  the  relative  fungicidal  values  of  lime  sulfur  and  Bor- 
deaux; (3)  the  advisability  of  interchanging  Bordeaux  arsenate  of 
lead  and  lime  sulfur  arsenate  of  lead;  (4)  the  efficiency  of  arsenate 
of  lead  without  a  fungicide  for  the  second  application;  (5)  the  value 
of  different  strengths  of  commercial  lime  sulfur;  (6)  the  fungicidal 
value  of  lime  sulfur  and  arsenate  of  lead  when  used  separately;  and 
(7)  the  individual  value  of  the  several  applications. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

The  experiments  of  1912  were  carried  on  in  the  same  orchard  as 
in  1910  and  1911,  but  in  a  more  desirable  block  of  trees  which  had 
come  into  full  bearing  since  the  selection  of  the  former  site.  The  trees 
were  twelve  years  old  and  in  a  very  vigorous  condition,  having  been 
given  excellent  care  ever  since  they  were  planted.  The  block  used 
consisted  of  three  hundred  Ben  Davis  trees.  It  was  divided  into  plats 
generally  numbering  four  trees  each. 

CHARACTER   OF  RECORDS  AND   METHOD  OF  MAKING 

Foliage  notes  were  taken  from  time  to  time  thruout  the  season, 
and  the  dropped  apples  were  counted  and  examined.  All  fruit  upon 
the  trees  at  harvesting  time  was  hand-picked,  counted,  and  weighed, 
and  the  entire  yield  from  a  representative  tree  in  each  plat  was  exam- 
ined. In  examining  the  apples  for  blemishes,  a  record  was  kept  of 
all  markings,  however  small.  In  the  tables,  the  term  "slight  scab"  re- 
fers to  a  very  slight  speck,  or  a  scab  so  small  as  to  pass  the  commer- 
cial grader  unnoticed.  By  "serious  scab"  is  meant  a  spot  or  number 
of  spots  sufficiently  large  to  keep  the  fruit  affected  from  the  grade  in 
which  it  otherwise  would  have  been  counted.  The  No.  1  apples  were 
graded  according  to  the  standards  described  in  the  Federal  Apple 
Package  and  Grade  Act,  the  No.  2's  by  an  arbitrary  standard  con- 
forming as  nearly  as  possible  to  the  average  No.  2  pack  of  the  com- 
mercial grower.  The  culls  included  all  not  in  the  No.  1  and  2  grades. 


1916} 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


89 


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90  BULLETIN  No.  185  [February, 

WEATHER  CONDITIONS 

The  weather  conditions  of  1912  were  very  nearly  normal.  There 
was  a  great  deal  of  rain  thruout  the  entire  summer,  but  at  no  time  was 
it  in  such  an  amount  or  of  such  duration  as  to  be  disastrous  for  or- 
chard operations.  The  harvest  season  was  ideal  for  taking  care  of  the 
fruit,  as  only  two  days  out  of  several  weeks  were  lost  on  account  of 
inclement  weather. 

The  trees  came  into  bloom  early  in  May.  The  weather  was  excel- 
lent for  pollination,  and  a  very  good  set  of  fruit  resulted.  During 
the  latter  part  of  the  blooming  period  a  heavy  rain  occurred,  which 
made  conditions  very  favorable  for  the  development  of  the  apple-scab 
fungus.  At  this  time  scab  was  first  visible  upon  the  foliage,  but  it 
was  four  weeks  later  that  the  first  scabby  apple  was  detected.  The 
attacks  were  quite  serious  at  times,  but  at  no  time  was  the  fungus 
active  over  a  very  long  period,  a  few  bright  days  generally  interven- 
ing between  the  stages  which  were  advantageous  for  its  development. 
The  unsprayed  or  check  trees  lost  most  of  their  fruit  and  foliage  sev- 
eral weeks  before  harvest  time,  and  that  fruit  which  remained  on  the 
trees  till  picking  time  was  very  scabby  and  showed  considerable  insect 
injury.  The  codling  moth  caused  very  little  injury,  and  altho  the 
curculio  did  some  damage,  it  was  more  or  less  irregular  in  its  attacks. 

SPRAY  DATES 

All  trees  which  were  to  receive  a  winter  application  were  sprayed 
April  13,  with  commercial  lime-sulfur  solution  diluted  1  in  15.  From 
one  to  five  summer  applications  were  made  upon  or  near  the  follow- 
ing dates :  April  27,  May  11,  May  23,  June  25,  and  August  6. 

FUNGICIDAL  VALUE  OF  WINTER  LIME  SULFUR 

The  winter  application  of  lime  sulfur  has  usually  been  made  only 
on  those  orchards  which  are  infested  with  San  Jose  scale.  The  bene- 
ficial effect  of  such  treatment  upon  the  general  appearance  of  the  trees 
has  been  sufficient  to  attract  attention.  It  has  also  been  observed  that 
in  certain  seasons  orchards  receiving  a  spraying  of  lime  sulfur  for 
San  Jose  scale  are  less  subject  to  severe  attacks  of  scab  than  adjoining 
orchards  from  which  the  winter  treatment  has  been  omitted.  In  order 
to  obtain  data  upon  the  fungicidal  value  of  this  treatment,  two  plats, 
each  consisting  of  sixteen  trees,  were  subdivided  into  sub-plats  of  four 
or  eight  trees  each  and  treated  as  shown  in  Table  13. 

EFFECT  ON  FOLIAGE 

A  small  amount  of  injury  to  the  green  tips  of  the  leaves  which 
received  the  winter  application  followed  the  treatment  given  Plat  B. 


1916} 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


91 


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92  BULLETIN  No.  185  [February, 

This  was  not  serious,  altho  the  first  leaves  were  dwarfed  thruout  the 
entire  season ;  otherwise  there  was  no  noticeable  difference  between  the 
appearance  of  the  trees  in  Plats  B  and  C.  Scab  was  first  noticed  on 
the  foliage  during  the  latter  part  of  the  blooming  period;  and  the 
infection  was  apparently  the  same  in  each  plat.  The  foliage  was 
dense  and  quite  vigorous,  and  held  on  until  removed  by  frost.  The 
amount  of  foliage  injury  for  which  the  spray  was  responsible  was  very 
temporary  and  negligible. 

EFFECT  ON  FRUIT 

There  was  a  very  heavy  set  of  fruit  on  all  plats.  It  was  picked 
and  examined  October  11,  with  the  results  presented  in  Table  13.  The 
percentage  of  apples  in  each  grade  as  determined  from  the  total  num- 
ber is  indispensable  to  those  interested  in  experimental  data  and  com- 
parisons, but  as  the  commercial  grower  is  particularly  interested  in 
the  percentage  as  based  on  the  number  of  bushels,  these  percentages 
are  also  given. 

The  use  of  a  winter  application  of  lime  sulfur  exerted  no  beneficial 
effect  in  checking  scab,  as  is  seen  by  comparing  the  records  of  Plat  B, 
which  received  this  application,  with  those  of  Plat  C,  which  was  not 
so  treated.  There  was  a  very  slight  variation  in  favor  of  Plat  B,  but 
the  difference  was  so  small  as  to  be  easily  within  a  possible  limit  of 
error. 

RELATIVE  EFFICIENCY  OF  LIME  SULFUR  AND  BORDEAUX 

Since  weather  conditions  determine  to  such  a  large  extent  the  effi- 
ciency of  a  fungicide,  an  experiment  was  again  conducted  to  gain  fur- 
ther data  upon  the  comparative  fungicidal  value  of  lime  sulfur  and 
Bordeaux.  Two  plats,  consisting  of  sixteen  trees  each,  were  sub- 
divided into  plats  of  four  or  eight  trees  and  treated  as  shown  in 
Table  14. 

EFFECT  ON  FOLIAGE 

The  earliest  infection  of  scab  was  noted  during  the  latter  part  of 
the  blooming  period.  Intervening  between  the  first  and  second  appli- 
cations several  rains  occurred  which  made  conditions  ideal  for  scab 
development,  and  at  the  same  time  washed  off  much  of  the  first  spray. 
Thruout  the  entire  season  the  trees  in  Plat  B  showed  more  scab  than 
those  in  Plat  A,  but  in  neither  plat  was  the  amount  sufficient  to  be 
injurious.  Upon  the  plats  receiving  the  fourth  and  fifth  applications, 
the  foliage  showed  practically  no  scab  spots  thruout  the  latter  part  of 
the  summer.  The  foliage  was  very  dense  and  vigorous  in  all  plats, 
and  spray  and  insect  injuries  were  negligible. 

EFFECT  ON  FRUIT 

The  trees  in  these  plats  gave  a  very  good  yield  of  fruit.  While  on 
the  trees,  the  apples  sprayed  with  lime  sulfur  appeared  to  be  better 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


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94  BULLETIN  No.  185  [February, 

colored  than  those  sprayed  with  Bordeaux,  but  after  the  fruit  was 
placed  on  the  sorting  table,  it  was  found  that  the  color  on  the  apples 
sprayed  with  Bordeaux  was  more  evenly  distributed  over  a  larger 
proportion  of  the  surface.  However,  the  apples  sprayed  with  lime 
sulfur  were  much  smoother  and  presented  a  better  polish,  while  upon 
close  inspection  many  of  the  apples  sprayed  with  Bordeaux  showed 
numerous  minute  black  specks. 

Records  were  obtained  upon  insect  injuries  and  certain  fungous 
diseases,  but  as  the  attacks  were  irregular  and  have  no  direct  bearing 
upon  the  experiment,  they  were  omitted  from  Table  14,  in  which  the 
fruit  data  of  this  experiment  are  presented. 

Considering  first  the  grade  columns  of  Table  14,  lime  sulfur  arsen- 
ate  of  lead  in  1912  did  very  effective  work,  being  somewhat  better 
than  Bordeaux  arsenate  of  lead.  The  comparative  efficiency  of  the 
two  mixtures  as  fungicides  is  designated  by  the  scab  columns.  Any 
difference  here  is  slightly  in  favor  of  Bordeaux  arsenate  of  lead,  but 
it  is  too  small  to  warrant  much  emphasis.  The  amount  of  russet  was 
decidedly  small  in  all  plats.  The  absolute  necessity  of  spraying  is 
shown  by  a  glance  at  the  records  of  the  apples  picked  from  trees  re- 
ceiving no  treatment. 

The  use  of  more  than  three  applications  seemed  unnecessary  at 
Neoga  in  1912,  as  the  variation  between  the  percentages  of  No.  1 
apples  in  the  different  plats  was  neither  so  regular  nor  so  varied  that 
any  definite  conclusions  might  be  drawn. 

EFFICIENCY  OF  LIME  SULFUR  ARSENATE  OF  LEAD  SUBSTITUTED  FOR 

BORDEAUX  ARSENATE  OF  LEAD  IN  ONE  OR  Two  OF  THE 

FIRST  THREE  REGULAR  SUMMER  APPLICATIONS 

For  a  number  of  years,  Bordeaux  has  been  the  standard  fungicide 
for  most  diseases  of  the  apple.  During  the  last  few  years,  the  use  in 
Illinois  of  lime  sulfur  as  a  substitute  for  Bordeaux  has  always  proved 
more  or  less  satisfactory,  particularly  in  certain  parts  of  the  state. 
In  order  to  see  if  a  combination  of  the  two  sprays  might  prove  effi- 
cient, that  is,  the  using  of  Bordeaux  for  one  or  more  applications  and 
lime  sulfur  for  the  others,  in  an  attempt  to  remove  the  undesirable 
qualities  of  each  spray  and  still  have  a  satisfactory  schedule,  three 
plats  were  treated  as  shown  in  Table  15. 

EFFECT  ON  FOLIAGE 

At  all  times  during  the  season,  Plat  4  showed  considerably  more 
scab  upon  the  foliage  than  did  any  of  the  other  plats.  This  was  espe- 
cially true  before  the  third  application  had  been  made.  A  small  num- 
ber of  yellow  leaves  formed  on  the  trees  in  Plats  3  and  4  shortly  after 
the  third  application,  but  these  soon  fell,  and  no  permanent  injury 
of  any  kind  was  apparent.  Some  of  the  leaves  on  trees  in  Plat  1  be- 


1916] 


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96  BULLETIN  No.  185  [February, 

came  brown  spotted  after  the  third  application,  but  this  was  notice- 
able for  only  a  few  days. 

EFFECT  ON  FRUIT 

The  fruit  upon  the  trees  in  these  plats  made  a  good  appearance, 
that  on  Plat  4  being  the  poorest.  The  crop  was  harvested  and  exam- 
ined on  October  15,  with  the  results  presented  in  Table  15. 

The  use  of  Bordeaux  arsenate  of  lead  for  the  first  application  and 
lime  sulfur  arsenate  of  lead  for  the  second  and  third  applications,  as 
in  Plat  1,  proved  the  most  satisfactory  treatment  of  this  group.  The 
trees  so  treated  yielded  fewer  scabby  apples  (18.59  percent  as  com- 
pared with  27.81  percent  and  25.2  percent  for  Plats  3  and  4)  ;  and 
the  percentage  of  No.  1  apples  was  nearly  20  percent  greater  than 
that  shown  by  either  of  the  other  treatments.  There  was  a  slight  vari- 
ation in  color  in  favor  of  Plats  3  and  4  over  Plat  1.  The  large 
amount  of  russet  in  Plat  1  compared  to  the  other  plats  was  rather 
unexpected.  The  effect  of  spraying  upon  the  size  of  the  apples  may 
be  seen  by  comparing  the  number  per  bushel  in  the  various  plats.  The 
unsprayed  apples  were  about  20  percent  smaller  than  the  sprayed 
apples. 

EFFICIENCY  OF  ARSENATE  OF  LEAD  WITHOUT  A  FUNGICIDE  FOR 
THE  SECOND  APPLICATION 

Because  of  the  tender  condition  of  the  small  apples  at  the  time  of 
the  second  application  and  the  injury  occasionally  following  the  use 
of  Bordeaux  arsenate  of  lead  at  that  time,  the  question  is  often  raised, 
Is  it  absolutely  necessary  to  use  a  fungicide  in  the  second  application  ? 
In  order  to  obtain  information  upon  this  point,  plats  were  treated  as 
shown  in  Table  16. 

EFFECT  ON  FOLIAGE 

As  the  season  advanced,  there  was  a  very  decided  difference  in  the 
general  appearance  of  the  trees  in  Plats  5  and  6  and  those  in  the 
other  two  Plats,  C  and  10,  in  which  the  treatment  differed  only  in 
regard  to  the  omission  of  the  fungicide  in  the  second  application. 
This  difference  could  be  distinguished  at  some  distance,  as  the  foliage 
in  the  two  former  plats  was  ragged,  and  about  one-half  of  it  fell  pre- 
maturely. The  most  serious  attack  of  scab  experienced  was  at  the 
blooming  period,  and  by  the  time  the  third  application  of  Bordeaux 
arsenate  of  lead  and  lime  sulfur  arsenate  of  lead  was  made  on  Plats  5 
and  6,  the  foliage  of  the  trees  in  these  plats  was  so  badly  infected 
with  scab  that  considerable  injury  followed  this  application.  In  the 
case  of  Plat  5,  which  received  the  lime  sulfur  arsenate  of  lead,  the 
injury  in  the  form  of  brown  spots  in  the  leaves  where  the  scab  spots 
were,  developed  within  a  few  hours  after  the  third  application.  In 
the  case  of  Plat  6,  which  received  Bordeaux  arsenate  of  lead,  no  in- 


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98  BULLETIN  No.  185  [February, 

jury  was  apparent  for  several  days,  when  many  of  the  leaves  turned 
yellow.  The  trees  in  both  Plats  5  and  6  lost  more  or  less  foliage  early 
in  the  season,  and  thruout  the  remainder  of  the  year  presented  a  less 
healthy  and  vigorous  appearance  than  did  those  in  Plats  C  and  10. 

EFFECT  ON  FRUIT 

The  apples  from  the  trees  in  Plats  5  and  6  were  of  very  poor  qual- 
ity. The  fruit  on  all  the  plats  was  picked  and  examined  October  15, 
with  the  results  given  in  Table.  16. 

The  necessity  of  a  fungicide  in  the  second  application,  the  spray 
immediately  after  the  bloom,  is  made  evident  by  these  results.  Dur- 
ing 1912  this  one  application  was  very  effective  in  the  control  of  scab, 
which  had  appeared  shortly  before  it  was  made.  From  the  results,  it 
would  seem  that  arsenate  of  lead  exerted  no  fungicidal  control  what- 
ever, since  those  plats  receiving  no  fungicide  in  the  second  applica- 
tion had  over  twice  as  many  scabby  apples  as  those  plats  receiving  a 
fungicide  at  that  time.  The  prolonged  efficiency  of  Bordeaux  as  com- 
pared with  lime  sulfur  arsenate  of  lead,  when  used  for  the  first  appli- 
cation, is  likewise  shown,  as  those  apples  receiving  Bordeaux  arsenate 
of  lead  in  the  first  application  were  considerably  freer  from  scab,  and 
yielded  nearly  twice  as  many  No.  1's  as  those  trees  receiving  lime 
sulfur  arsenate  of  lead  preceding  the  bloom.  The  difference  in  the  size 
of  the  apples  from  Plats  5  and  6  was  also  noticeable,  those  from  Plat  6 
being  over  20  percent  larger  than  those  from  Plat  5. 

VALUE  OF  DIFFERENT  STRENGTHS  OF  COMMERCIAL  LIME  SULFUR 

Since  the  introduction  of  lime  sulfur  for  the  summer  treatment  of 
apples,  the  question  regarding  the  most  effective  dilution  to  use  has 
been  raised.  In  order  to  gain  information  upon  this  point,  applica- 
tions were  made  as  shown  in  Table  17. 

EFFECT  ON  FOLIAGE 

Up  to  the  middle  of  the  summer  there  was  no  apparent  difference 
in  the  general  appearance  of  the  trees  in  these  plats,  and  the  number 
of  leaves  showing  scab  was  quite  small.  No  injury  of  any  kind  fol- 
lowed the  use  of  any  of  these  strengths.  All  the  foliage  was  dark 
green  and  dense,  and  attracted  the  attention  of  all  visitors,  even  the 
trees  which  received  the  weakest  solution  possessing  almost  perfect 
foliage.  During  the  second  week  of  August,  however,  serious  infec- 
tion of  scab  began  to  show  on  all  the  trees  in  all  plats  excepting 
Plat  16,  and  from  that  time  the  general  appearance  became  less  and 
less  attractive,  until  at  harvest  time  all  the  trees  but  those  in  Plat  16 
were  nearly  one-third  defoliated,  and  what  leaves  remained  were 
scabby  and  ragged. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


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100  BULLETIN  No.  185  [February, 

EFFECT  ON  FRUIT 

The  fruit  from  these  plats,  excepting  Plat  16,  appeared  before 
picking  to  be  of  very  poor  quality  and  lacking  in  good  color,  and  on 
being  placed  on  the  sorting  table  it  proved  to  be  no  better.  All  the 
plats  were  harvested  and  the  fruit  was  examined  October  17,  with  the 
results  presented  in  Table  17. 

The  dilution  commonly  recommended  of  one  gallon  of  commercial 
lime-sulfur  solution  to  40  of  water,  or  thereabouts,  gave  the  most 
satisfactory  results  in  this  experiment.  It  will  be  seen  in  comparing 
the  apples  sprayed  with  solutions  both  stronger  and  weaker  than  1 
to  40,  that  there  seems  to  be  very  little  difference,  as  the  variation  in 
the  number  of  No.  1  's  is  about  8  percent,  and  the  greatest  differ- 
ence of  scab  is  less  than  10  percent.  This  experiment  opens  up  a  new 
line  of  investigation ;  namely,  the  determining  of  the  effect  of  varying 
amounts  of  arsenate  of  lead  with  a  definite  dilution  of  lime  sulfur, 
since  it  is  evident  that  the  amount  of  reaction  resulting  between  lime 
sulfur  and  arsenate  of  lead  determines  to  some  extent  the  efficiency 
of  the  mixture.  It  may  be  assumed  from  these  data  that  the  proper 
reaction  from  a  dilution  of  commercial  lime  sulfur,  1  to  40,  with  4 
pounds  of  arsenate  of  lead  per  100  gallons  of  spray  results  in  a  very 
satisfactory  fungicide. 

FUNGICIDAL  VALUE  OF  LIME  SULFUR  AND  ARSENATE  OF  LEAD 
WHEN  USED  SEPARATELY 

Experiments  in  previous  years  have  shown  lime  sulfur  arsenate  of 
lead  to  be  much  more  effective  as  a  fungicide  than  lime  sulfur  used 
alone.1  In  order  to  gain  further  data  on  this  point;  three  plats  were 
sprayed  as  shown  in  Table  18. 

EFFECT  ON  FOLIAGE 

By  the  time  of  the  second  application  the  foliage  of  the  trees  in 
Plats  33  and  35  was  badly  infected  with  scab,  while  that  in  Plat  29 
showed  only  a  small  amount.  As  a  result  of  this  serious  infection 
the  second  and  third  applications  to  Plats  33  and  35  caused  so  much 
spray  injury  that  practically  all  the  foliage  was  brown  spotted  and 
ragged,  and  by  the  middle  of  the  summer  these  trees  were  over  50 
percent  defoliated.  At  the  end  of  the  season  they  presented  very  little 
difference  in  appearance  from  the  check  trees. 

EFFECT  ON  FRUIT 

With  the  exception  of  Plat  29,  the  fruit  from  these  plats  was  of 
very  poor  quality.  It  was  picked  and  examined  October  18,  with  the 
results  presented  in  Table  18. 

'See  p.  87. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


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102  BULLETIN  No.  185  [February, 

The  increased  efficiency  of  lime  sulfur  combined  with  arsenate  of 
lead  over  lime  sulfur  alone  was  plainly  evident,  as  is  shown  by  the 
data  presented.  Arsenate  of  lead  used  alone  was  of  practically  no 
fungicidal  value  in  this  experiment. 

Attention  is  called  to  a  comparison  of  Plat  29  in  Table  18, 
and  Plat  C  in  Table  16,  page  97.  The  treatments  of  these  two  plats 
varied  only  in  the  time  of  spraying,  as  each  was  given  three  applica- 
tions of  1-40-4-100  lime  sulfur  arsenate  of  lead.  Plat  29  was,  in  each 
case,  sprayed  three  to  four  days  later  than  Plat  C,  and  since  Plat  C 
yielded  nearly  20  percent  more  No.  1's  than  Plat  29,  and  showed 
50  percent  less  scab,  the  time  of  application  is  again  shown  to  be  an 
important  factor  which  must  not  be  lost  sight  of. 

INDIVIDUAL  VALUE  or  THE  SEVERAL  APPLICATIONS 

In  order  to  show  the  value  of  each  of  the  first  three  regular  sum- 
mer applications  when  used  separately,  five  plats  were  treated  as 
shown  in  Table  19.  The  applications  were  made  at  the  time  consid- 
ered most  effective  for  each. 

EFFECT  ON  FOLIAGE 

The  trees  of  Plat  37,  which  received  the  first  application  of  Bor- 
deaux arsenate  of  lead,  showed  the  healthiest  foliage  of  all  the  plats. 
Altho  only  a  very  small  percentage  of  the  foliage  of  the  trees  in  this 
plat  received  any  spray,  the  early  infection  of  scab  was  held  in  check 
remarkably  well,  and  only  a  small  percentage  of  the  foliage  was  lost 
before  the  normal  defoliation.  The  trees  in  the  other  plats  were  all 
badly  infected  with  scab  at  the  time  the  applications  were  made,  and 
altho  the  disease  appeared  to  be  held  in  check  temporarily,  the  effect 
of  the  spray  extended  over  only  a  short  period. 

As  a  result  of  the  application,  the  trees  in  each  of  the  plats  receiv- 
ing the  second  or  third  spraying  only  showed  considerable  injury. 
On  the  trees  sprayed  with  lime  sulfur  this  became  apparent  within 
a  few  hours,  but  with  the  Bordeaux-sprayed  trees  several  days  elapsed 
before  the  injury  developed.  The  trees  in  Plats  38  and  39  lost  about 
40  percent  of  their  foliage,  and  those  in  Plats  40  and  41  about  25 
percent.  At  the  close  of  the  season,  the  foliage  in  all  plats  was  ragged, 
and  insect  and  fungous  injuries  were  very  apparent. 

EFFECT  ON  FRUIT 

The  appearance  of  the  apples  on  the  trees  in  these  plats  before 
picking,  except  in  Plat  37,  was  little  better  than  that  on  the  check 
trees.  The  fruit  was  picked  and  examined  October  28,  with  the  re- 
sults presented  in  Table  19. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  103 

This  table  shows  the  ineffectiveness  of  single  applications.  In  1912 
the  first  application  proved  considerably  more  effective  in  the  control 
of  scab  than  the  second  or  third,  as  it  was  applied  shortly  before  the 
first  outbreak  of  the  infection.  This  treatment  also  produced  nearly 
100  percent  more  No.  1's  than  any  of  the  other  treatments.  Single 
applications  of  Bordeaux  arsenate  of  lead  are  somewhat  more  efficient 
than  the  same  applications  of  lime  sulfur  arsenate  of  lead. 

SUMMARY  OF  RESULTS  AT  NEOGA,  1912 

1.  No  beneficial  results  in  the  control  of  scab  were  obtained  from 
the  winter  application  of  lime  sulfur. 

2.  Lime  sulfur  arsenate  of  lead  was  slightly  less  efficient  in  the 
control  of  scab  than  Bordeaux  arsenate  of  lead. 

3.  Three,  four,  and  five  applications  of  lime  sulfur  arsenate  of 
lead  yielded  as  many  No.  1  apples  as  the  same  number  of  Bordeaux 
arsenate  of  lead  applications. 

4.  The  most  satisfactory  treatment  consisted  of  Bordeaux  arsen- 
ate of  lead  for  the  first  application,  and  lime  sulfur  arsenate  of  lead 
for  the  second  and  third  applications. 

5.  Arsenate   of  lead  alone  possesses  practically  no  fungicidal 
value,  and  because  of  possible  injury  to  the  foliage  should  never  be 
used  as  an  apple  spray  except  in  combination  with  a  fungicide. 

6.  Commercial  lime-sulfur  solution  diluted  1  in  40,  and  applied 
with  4-100  arsenate  of  lead,  is  much  more  effective  than  any  other 
dilution. 

7.  Lime  sulfur  arsenate  of  lead  is  a  very  much  more  effective 
fungicide  than  lime  sulfur  alone. 

8.  The  time  of  application  is  a  determining  factor  in  the  effect- 
iveness of  lime  sulfur  arsenate  of  lead. 

9.  It  is  inadvisable  to  omit  any  of  the  first  three  regular  appli- 
cations. 


104  BULLETIN  No.  185  [February, 

SPRAYING  EXPERIMENTS  IN  1912  AT  FLORA, 
CLAY  COUNTY 

BY  W.  A.  EUTH,  ASSOCIATE  IN  HORTICULTURAL  CHEMISTRY 

OBJECTS 

About  half  the  spraying  experiment  at  Flora  in  1912  was  devoted 
to  a  comparison  of  Bordeaux  and  lime  sulfur.  The  remainder  of  the 
experiment  consisted  in  a  comparison  of  Sherwin-Williams,  Heming- 
way, and  Grasselli  arsenates  of  lead,  tests  of  copper  i'errocyanide,  and 
a  trial  of  the  mixtures  resulting  from  the  addition  of  copper  sulfate 
and  lead  acetate  to  lime  sulfur. 

LOCATION  AND  DESCRIPTION  OP  ORCHARD 

The  orchard  in  which  the  experiments  were  carried  out  was  situ- 
ated four  and  one-half  miles  west  of  Flora,  in  the  southwestern  part 
of  Clay  county,  a  little  north  and  east  of  the  center  of  the  southern 
horticultural  district,  which  includes  the  southern  third  of  the  state. 
The  trees  were  sixteen  years  old  and  were  planted  30  feet  apart  each 
way.  There  were  17  rows  north  and  south,  and  from  40  to  45  rows 
east  and  west.  The  north  four  rows  and  the  south  six  rows  were 
Ben  Davis;  the  center  seven  rows  were  Jonathan.  Mr.  John  Eggin- 
ton,  the  original  owner  of  this  orchard,  was  the  pioneer  fruit  grower 
of  the  locality.  For  several  years  after  the  trees  were  planted,  the 
orchard  was  cared  for  by  Mr.  Egginton;  since  1906  it  had  been  in  the 
hands  of  the  Experiment  Station.  The  trees  were  in  a  thrifty  con- 
dition. 

The  orchard  sloped  gradually  and  evenly  to  the  west,  the  extreme 
western  end  being  about  thirty  feet  lower  than  the  eastern  end.  The 
spraying  experiments  were  confined  to  the  upper,  or  eastern,  half  of 
the  orchard.  Tests  made  early  in  the  season,  on  still  nights,  showed 
no  appreciable  difference  between  the  temperature  of  the  lower  and 
upper  ends  of  the  part  in  which  the  spraying  experiments  were  car- 
ried out,  showing  that  there  was  good  air  drainage,  and  that  there 
was  not  sufficient  difference  in  elevation  to  cause  a  possible  difference 
in  conditions  favoring  russeting  or  fungous  infection. 

The  trees  in  the  western  end,  which  were  not  included  in  the  ex- 
periments, were  sprayed  three  times.  An  open  field  of  fourteen  acres 
lay  directly  to  the  north,  and  an  older  orchard,  unsprayed,  joined  the 
experimental  plats  on  the  south.  A  fourteen-acre  orchard  of  trees 
twenty-six  years  old,  used  by  the  station  for  fertilizer  experiments, 
lay  to  the  east. 

TREATMENT 

Table  20  specifies  the  materials  used  for  the  applications  on  each 
plat.  Plats  4  to  11,  which  constitute  the  principal  part  of  the  experi- 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


105 


TABLE  20. — SPRAY  MATERIALS  USED  IN  THE  EXPERIMENTS  AT  FLORA,  19121 


Plat 

First 
application 
(April  23-24) 

Second 
application 
(May  10-13) 

Third 
application 
(May  27-29) 

Fourth 
application 
(July  1-5) 

1 

Lime  sulfur  and 

Lime  sulfur  and 

Lime  sulfur  and 

Bordeaux 

lead  acetate 

lead  acetate 

lead  acetate 

2 

Lime  sulfur2 

Lime  sulfur2 

Lime  sulfur2 

Bordeaux* 

3 

Lime  sulfur3         -  . 

Lime  sulfur3 

Lime  sulfur8 

Bordeaux1 

4 

Lime  sulfur 

Lime  sulfur 

Lime  sulfur 

Bordeaux 

5 

Lime  sulfur 

Lime  sulfur 

Bordeaux 

Bordeaux 

6 

Lime  sulfur 

Bordeaux 

Lime  sulfur 

Bordeaux 

7 

Lime  sulfur 

Bordeaux 

Bordeaux 

Bordeaux 

8 

Bordeaux 

Bordeaux 

Bordeaux 

Bordeaux 

9 

Bordeaux 

Bordeaux 

Lime  sulfur 

Bordeaux 

10 

Bordeaux 

Lime  sulfur 

Lime  sulfur 

Bordeaux 

11 

Bordeaux 

Lime  sulfur 

Bordeaux 

Bordeaux 

12 
13 
14 

Copper  ferro- 
cyanide 
Copper  ferro- 
cyanide  alone4 
Lime  sulfur  and 

Copper  ferro- 
eyanide 
Copper  ferro- 
cyanide  alone 
Lime  sulfur 

Copper  ferro- 
cyanide 
Copper  ferro- 
cyanide  alone 
Lime  sulfur 

Copper  ferro- 
cyanide 
Copper  ferro- 
cyanide  alone 
Bordeaux 

copper  sulfate 

3Grasselli  paste  arsenate  of  lead  was  used  in  combination  with  the  fungicide 
on  all  plats  except  where  noted,  at  the  rate  of  4  pounds  to  100  gallons  of  spray. 

'Hemingway  paste  arsenate  of  lead  was  used  on  this  plat,  at  the  rate  of  4 
pounds  to  100  gallons  of  spray. 

3Sherwin-Williams  paste  arsenate  of  lead  was  used  on  this  plat  at  the  rate  of 
4  pounds  to  100  gallons  of  spray. 

4No  arsenate  of  lead  was  used  on  this  plat. 

ment,  were  treated  for  the  purpose  of  testing  the  relative  merits  of 
Bordeaux  and  lime  sulfur.  On  all  these  plats  Grasselli  arsenate  of 
lead  was  used,  thereby  keeping  the  insecticide  constant.  Lime  sulfur 
and  Bordeaux  were  interchanged  in  all  possible  ways  for  the  first 
three  applications. 

The  fourth  application,  in  all  cases,  with  the  exception  of  the  two 
plats,  12  and  13,  on  which  copper  ferrocyanide  was  used,  consisted  of 
Bordeaux  arsenate  of  lead.  A  small  yield  necessitated  a  choice, 
of  either  Bordeaux  or  lime  sulfur  for  this  application.  Bordeaux  was 
used  because  it  was  thought  that  by  this  time  the  fruit  would  be  out 
oi'  danger  of  russet,1  and  because  of  the  danger  of  burning  the  fruit 
by  using  lime  sulfur  during  the  hot  weather.  If  the  yield  had  been 
heavier,  lime  sulfur  would  have  been  applied  to  one  half  of  each  plat 
at  this  time,  and  Bordeaux  to  the  other  half,  in  order  to  determine 
more  fully  their  relative  efficiency  in  the  control  of  blotch  as  well  as 
their  tendency  to  cause  foliage  and  fruit  injury. 

Plat  A,  shown  in  Chart  5,  which  was  to  have  been  used  to  com- 
pare the  results  of  heavy  and  light  spraying,  was  abandoned,  as  far  as 
experimental  purposes  were  concerned,  because  weather  conditions 
early  in  the  season  interfered  with  its  being  sprayed  properly. 

^edrick,  U.  P.,  N.  Y.  (Geneva)  Agr.  Exp.  Sta.  Bui.  287,  p.  163,  1907. 


106 


BULLETIN  No.  185 


[February, 


POOOP 
OOOOO 


pooop 

OOOOO 


POOQQ 
OOOOO 


poooo 

OOOOO 


oopoooo 

OQOOOOO 


opoooo 
oooooo 


ipOOOO 

'OOOOO 


poooo 

•OOOOO 


poooo 

OOOOO 


poooo 

OOOOO 


poooo 

OOOOO 


'••f 

fwl 


12; 


Ben  Davis 
Check. 


Jonathan 
Check. 


Ben  Davia.  Jonathan.        ( 

CHART  5. — PLAN  OF  PLATS  IN  ORCHARD  OF  MRS.  JOHN  EGGINTON,  FLORA,  1912 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLK  ORCHARDS  107 

For  arrangement  of  plats  see  Chart  5. 

The  first  application  of  spray  was  made  just  before  the  trees 
bloomed,  April  23-24 ;  the  second,  within  ten  days  after  the  petals  fell, 
May  10-13 ;  the  third,  three  weeks,  May  27-29,  and  the  fourth,  eight 
weeks,  July  1-5,  after  the  petals  fell.  The  foliage  was  dense  and  re- 
quired exceptionally  heavy  applications  of  spray,  even  before  the 
bloom.  An  average  of  5.5  gallons  of  spray  was  used  per  tree  for  the 
first  application,  8.5  gallons  per  tree  for  the  second,  7  gallons  for  the 
third,  and  7.5  gallons  for  the  fourth.  The  foliage  was  sprayed  until 
it  began  to  drip. 

So  far  as  possible,  Plats  4  to  11,  inclusive,  were  sprayed  on  the 
same  days.  Plats  1,  2,  3,  and  14  were  then  sprayed,  followed  by  Plats 
12  and  13. 

APPARATUS  AND  MATERIALS 

Bean  whirlpool  nozzles  were  used  except  for  the  application  imme- 
diately following  the  fall  of  the  petals  (the  second),  when  Friend 
"Drive  Spray"  nozzles  were  used.  The  material  was  applied  with  a 
power  outfit  at  a  pressure  of  225  to  250  pounds. 

The  lime  sulfur  was  made  according  to  the  Illinois  formula  (50 
pounds  lime,  100  pounds  sulfur,  boiled  at  a  volume  of  66  gallons), 
and  diluted  at  the  rate  of  1  in  18. 

The  Bordeaux  used  was  the  standard  8-8-100  mixture.  It  was 
made  by  pumping  about  50  gallons  of  water  into  the  tank  with  the 
tank  filler,  adding  the  stock  solution  of  lime  thru  the  strainer  with  the 
tank  filler  going,  adding  the  arsenate  of  lead,  making  up  to  100  gal- 
lons, and  then  slowly  adding  the  stock  solution  of  copper  sulfate,  con- 
taining 1  pound  to  the  gallon,  to  the  stream  from  the  tank  filler  as  it 
entered  the  strainer.  The  force  of  the  water  from  the  tank  filler  and 
the  whirling  and  splashing  in  the  strainer  were  relied  upon  to  dilute 
the  copper  sulfate  before  it  entered  the  diluted  lime.  Tests  with  the 
mixture  from  the  tank  showed  that  it  remained  in  suspension  as  long 
as  a  mixture  made  by  any  other  method. 

The  copper  ferrocyanide  used  was  made  at  equal  and  full  dilution, 
at  the  rate  of  2  pounds  of  copper  sulfate  and  2  pounds  of  potassium 
ferrocyanide  to  100  gallons  of  water.  The  fully  diluted  potassium 
ferrocyanide  was  run  into  the  fully  diluted  copper  sulfate. 

The  mixture  of  copper  sulfate,  lime  sulfur,  and  arsenate  of  lead 
for  Plat  14  contained  4  pounds  of  copper  sulfate  in  100  gallons  of  the 
ordinary  diluted  lime  sulfur  arsenate  of  lead.  It  was  made  by  pour- 
ing the  stock  solution  of  copper  sulfate  slowly  into  the  water  running 
from  the  tank  filler  into  the  strainer,  after  the  lime  sulfur  and  arsen- 
ate of  lead,  previously  placed  in  the  tank,  had  been  diluted  to  about 
half  the  final  volume.  The  method  used  for  making  the  lead  acetate, 
lime  sulfur,  arsenate  of  lead  spray  was  the  same  except  that  lead 
acetate  was  used  instead  of  copper  sulfate.  Four  pounds  of  lead 
acetate  were  used  to  each  100  gallons  of  spray. 


108  BULLETIN  No.  185  [February, 

CHARACTER  OF  RECORDS  AND   METHOD  OF  MAKING 

The  date,  the  hour  of  commencing  and  the  hour  of  completing 
the  spraying  of  each  plat,  the  amount  of  spray  applied,  the  pressure 
used,  the  direction  and  strength  of  wind,  and  the  general  weather 
conditions  were  recorded  at  the  time  of  each  application.  Records 
were  made  from  time  to  time  on  the  fruit  and  foliage,  describing  the 
spray  present,  the  first  appearance  and  the  progress  of  fungous  in- 
fection, and  the  character  of  spray  and  insect  injury.  Maximum  and 
minimum  temperatures,  the  wet-  and  dry-bulb  temperatures  at  7  a.  m.,  - 
12  m.,  and  6  p.  m.,  and  the  rainfall,  were  recorded  during  the  entire 
season. 

Dropped  apples  were  examined  during  September  for  insect,  fun- 
gous, and  spray  injuries.  Records  from  the  picked  apples  were  made 
on  slight  and  severe  infections  of  dead  and  live  scab,  blotch,  sooty 
blotch,  and  flyspeck,  slight  and  severe  russeting,  calyx  and  side  in- 
juries by  codling  moth,  and  slight  and  severe  curculio  injuries.  There 
was  no  bitter  rot.  The  term  "severe"  means  an  injury  sufficient  to 
class  an  individual  apple  as  a  cull  under  a  careful  system  of  grading. 
Slight  and  severe  infections  are  considered  together  in  the  report  of 
the  results  (Table  21). 

Because  of  a  very  light  bloom  some  of  the  Ben  Davis  plats  did  not 
yield  much  over  one  hundred  apples,  and  most  of  the  Jonathan  plats 
between  one  hundred  and  two  hundred  apples,  in  one  case  less  than 
one  hundred.  The  entire  crop  was,  therefore,  examined. 

WEATHER  CONDITIONS 

During  April,  May,  and  June,  the  rainfall  was  well  distributed. 
There  were  no  severe  drops  in  temperature  except  on  the  morning  of 
May  13,  when  a  minimum  of  33°  was  recorded  in  the  thermometer 
box  at  the  upper  end  of  the  orchard.  There  is  a  possibility  that  a 
thermometer  so  placed  does  not  always  record  the  lowest  temperature 
among  the  trees  themselves,  so  that  a  low  temperature  on  that  night 
may  have  been  an  active  factor  in  the  formation  of  russet.  Favorable 
weather  accompanied  the  first  application,  but  the  second,  third,  and 
fourth  applications  were  interrupted  by  rain.  There  was  also  a  heavy 
fall  of  rain  just  after  the  completion  of  each  application.  During  the 
early  part  of  July,  there  was  an  excessive  amount  of  rain,  but  the 
remainder  of  the  season  was  normal. 

EFFECT  OF  SPRAYS  ON  FOLIAGE 

The  effect  of  the  sprays  on  the  foliage  was  studied  from  the  stand- 
point of  the  amount  of  injury  caused  as  well  as  the  protection  af- 
forded. 

Scab. — The  foliage  on  all  plats,  unsprayed  as  well  as  sprayed,  was 
practically  free  from  scab. 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  109 

Leaf  Spot. — Leaf  spot  caused  severe  loss  of  foliage  on  the  check 
plats  during  the  latter  part  of  the  season.  It  was  much  more  severe 
on  the  Ben  Davis  than  on  the  Jonathans.  Up  to  the  first  of  Septem- 
ber there  had  been  very  little  loss  of  foliage  from  this  fungus,  but  by 
the  first  of  October  the  check  Ben  Davis  trees  had  become  practically 
defoliated.  So  far  as  could  be  told,  all  the  treatments  afforded  com- 
plete protection,  altho  it  must  be  borne  in  mind  that  lime  sulfur  was 
not  used  for  the  fourth  application ;  the  only  sprays  used  at  that  time 
were  Bordeaux  and  copper  ferrocyanide.  The  necessity  of  spraying 
orchards  in  this  locality  to  prevent  defoliation  by  leaf  spot  is  shown 
in  Plates  3  and  4,  page  208.  The  trees  in  good  foliage  were  sprayed 
three  times;  before  the  bloom  with  Bordeaux  arsenate  of  lead,  just 
after  the  petals  fell  with  lime  sulfur  arsenate  of  lead,  and  two  weeks 
later  with  Bordeaux  arsenate  of  lead.  The  others  were  not  sprayed. 

Insect  Injuries. — An  insect  not  often  observed  in  former  years  by 
commercial  growers  in  this  locality,  but  which  was  present  this  year 
in  large  numbers,  was  the  apple  flea-weevil.  It  is  described  by  Dr.  S. 
A.  Forbes1  as  follows : 

"The  apple  flea- weevil  is  a  small,  dull  blackish  beetle  nearly  one- 
eighth  of  an  inch  long,  resembling  the  common  flea-beetles  in  general 
appearance ;  and,  altho  a  true  weevil  or  snout-beetle,  it  has  the  power 
of  leaping  like  the  flea-beetles.  The  larvae  make  winding  burrows 
(mines)  in  apple  leaves ;  the  pupae  are  formed  within  the  leaf ;  and  the 
adults  feed  on  the  leaves,  making  numerous  shallow  pits  which  later 
become  small  holes.  The  eggs  are  apparently  inserted  in  the  outer 
part  of  the  leaf  in  one  of  the  principal  veins. ' ' 

By  the  middle  of  May,  almost  every  leaf  showed  the  work  of  the 
larval  stage  of  this  insect.  During  the  latter  part  of  May  and  the  first 
part  of  June,  one  or  two  adult  insects  were  to  be  found  feeding  on  the 
under  side  of  almost  every  leaf,  where  all  the  feeding  was  done.  The 
insects  had  almost  disappeared  by  June  24.  Altho  the  third  applica- 
tion was  made  on  May  27  and  28,  when  the  insects  were  most  numer- 
ous, the  sprays  were  ineffective  in  controlling  them.  The  care  taken  in 
spraying,  the  high  pressure  of  225  to  250  pounds,  and  the  large  amount 
of  spray  used,  should  have  controlled  the  apple  flea-weevil,  if  it  were 
possible  to  do  so  by  means  of  arsenate  of  lead,  Bordeaux,  or  lime  sul- 
fur. No  especial  pains  were  taken  to  spray  the  under  sides  of  the 
leaves,  however. 

Bordeaux  Injury. — Bordeaux  injury  did  not  appear  until  June  20, 
which  was  about  three  weeks  after  the  third  application.  This  rela- 
tively late  appearance  of  injury,  in  spite  of  heavy  rains  which  came 
soon  after  the  second  and  third  applications,  and  which  it  has  been 
found  are  in  general  followed2  by  the  appearance  of  the  injury,  may 
possibly  be  set  down  to  the  vigorous  condition  of  the  trees.3  On  June 

Torbes,  S.  A.,  Twenty-sixth  Eeport,  Illinois  State  Entomologist,  pp.  83-85, 
1911. 

2Hedrick,  U.  P.,  N.  Y.  (Geneva)  Agr.  Exp.  Sta.  Bui.  287,  pp.  166-169,  1907. 
"Crandall,  C.  S.,  111.  Agr.  Exp.  Sta.  Bui.  135,  p.  223,  1909. 


110  BULLETIN  No.  185  [February, 

20,  leaf-yellowing  showed  slightly  on  the  plats  on  which  Bordeaux 
had  been  used  for  the  second  or  third  application,  or  both.  There  was 
none  on  Plat  10,  which  had  received  Bordeaux  for  the  first  application 
only.  By  June  24,  the  injury  from  the  second  and  third  applications 
had  become  very  severe,  a  great  many  leaves  turning  yellow  and  a  con- 
siderable number  falling.  On  July  1  the  attack  of  leaf-yellowing  had 
about  passed. 

Following  the  fourth  application,  made  between  July  1  and  July 
5,  there  was  no  severe  leaf-yellowing  until  the  first  week  in  August. 
On  August  7  the  injury  had  become  very  severe  on  all  the  Jonathans 
sprayed  the  fourth  time  with  Bordeaux.  This  included  all  the  sprayed 
plats  except  those  sprayed  with  copper  ferrocyanide,  on  which  there 
was  no  injury  at  this  time.  There  was  much  less  injury  on  the  Ben 
Davis  trees  than  on  the  Jonathans.  The  attack  had  developed  fully 
and  the  trees  had  lost  most  of  their  injured  leaves  by  August  20,  the 
damage  having  become  somewhat  severe  on  the  Ben  Davis  and  very  se- 
vere on  the  Jonathans.  No  serious  attacks  of  leaf -yellowing  as  a  re- 
sult of  Bordeaux  injury  appeared  after  August  20. 

Altho  it  is  possible  that  the  large  amount  of  spray,  together  with 
the  high  pressure  and  rather  coarse  nozzles,  was  responsible  for  the 
severity  of  the  Bordeaux  injury  to  the  fruit,  reported  later  in  Tables 
21  and  22,  the  injury  to  the  foliage  was  no  greater  than  that  caused  in 
certain  other  orchards  in  the  neighborhood  where  the  pressures  used 
were  lower,  and  where  smaller  amounts  of  spray  were  applied.  Com- 
parisons with  other  orchards  in  respect  to  foliage  injury  are  not  wholly 
justified  because  of  other  varying  factors,  but  there  were  no  experi- 
ments in  this  orchard  in  which  low  pressures  and  small  amounts  of 
spray  were  used. 

Injury  from  Oilier  Sprays. — It  was  observed  by  Wallace1  that  in- 
juries occur  where  lime  sulfur  is  applied  to  foliage  which  has  been  at- 
tacked by  apple  scab.  As  no  lime-sulfur  injury  occurred  in  any  of  the 
plats  where  lime  sulfur  was  used  in  these  experiments,  and  as  there 
was  no  apple  scab,  the  inference  may  be  drawn  from  these  results  also 
that  lime  sulfur  can  be  applied  to  healthy  foliage  with  but  slight  dan- 
ger of  injuring  it. 

There  was  very  little  foliage  injury  due  to  the  use  of  copper  ferro- 
cyanide. The  spray  was  very  adhesive.  On  August  20  the  foliage  on 
the  copper-ferrocyanide  plats  (Plats  12  and  13)  was  much  heavier 
than  that  on  any  of  the  other  sprayed  plats,  all  of  which  by  this  time 
had  received  Bordeaux. 

Lime  sulfur,  copper  sulfate,  and  arsenate  of  lead  when  used  for 
the  first  application  (Plat  14),  caused  no  foliage  injury.  This  spray 
acted  similarly  to  Bordeaux  in  this  respect. 

'Wallace,  Errett,  N.  Y.   (Cornell)  Agr.  Exp.  Sta.  Bnl.  288,  pp.  123-126,  1910. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  111 

Lime  sulfur,  lead  acetate,  and  arsenate  of  lead  when  used  for  the 
first  three  applications  (Plat  1),  caused  no  foliage  injury.  The  spray 
was  black  at  first,  but  lost  its  color,  looking  in  about  ten  days  like  the 
ordinary  lime  sulfur  arsenate  of  lead. 

EFFECT  ON  FRUIT 

The  effects  of  the  treatments  on  the  fruit  are  shown  in  Table  21. 

Scab. — Scab  first  appeared  May  18,  when  a  very  little  was  ob- 
served on  the  Ben  Davis  foliage.  The  development  of  scab  on  this 
variety  was  so  slight  that  at  picking  time  only  15.2  percent  of  the 
apples  from  the  check  plats  showed  infection,  while  the  Jonathans 
were  entirely  free.  All  of  the  sprays  controlled  scab  almost  perfectly. 
The  infection  was  so  slight  that  no  conclusions  can  be  drawn  from 
the  results. 

Blotch. — The  outbreak  of  blotch  was  so  severe  that  the  year  was  a 
favorable  one  for  studying  its  control  under  extreme  conditions.  On 
an  average,  67.1  percent  of  the  apples  from  the  Jonathan  check  plats, 
and  72.7  percent  of  the  apples  from  the  Ben  Davis  check  plats,  showed 
blotch  at  picking  time. 

The  first  appearance  of  this  fungus  on  the  fruit  was  June  17,  when 
it  was  observed  on  a  very  few  Ben  Davis  apples.  On  July  17  approxi- 
mately 10  percent  of  the  apples  of  this  variety  showed  infection,  and 
it  was  just  appearing  on  the  Jonathans.  The  Jonathans  at  this  time 
were  showing  about  as  much  blotch  as  the  Ben  Davis  had  shown  a 
month  before. 

Keference  to  Table  21  will  show  that  all  the  treatments  con- 
trolled the  blotch  on  the  Jonathans  almost  perfectly.  It  has  been 
mentioned  previously  that  the  last  application  on  all  but  the  copper- 
ferrocyanide  plats  (Plats  12  and  13)  was  Bordeaux,  and  that  this 
application  was  made  July  1-5,  while  the  first  scattering  infection  of 
blotch  on  this  variety  was  observed  July  17.  Bordeaux  was  thus  pres- 
ent on  the  Jonathan  apples  at  the  period  of  greatest  infection. 

The  control  of  blotch  on  the  Ben  Davis  was  scarcely  as  good  as  it 
was  on  the  Jonathans,  except  where  Bordeaux  was  the  only  or  the 
principal  fungicide  applied.  However,  lime  sulfur  arsenate  of  lead 
when  used  for  the  first  three  applications,  with  Bordeaux  for  the 
fourth  (Plats  2,  3,  and  4),  controlled  a  very  large  proportion  of  the 
infection,  the  fungus  showing  on  only  3.5  to  4  percent  of  the  apples 
so  treated.  Bordeaux,  when  used  for  all  four  applications,  gave  per- 
fect control. 

Where  copper  ferrocyanide  and  arsenate  of  lead  were  used  (Plat 
12),  there  was  no  blotch  on  the  Jonathans,  while  there  was  27.5  per- 
cent on  the  Ben  Davis.  Where  copper  ferrocyanide  was  used  alone 
(Plat  13),  1.8  percent  of  the  Jonathans  showed  blotch,  while  35.5 
percent  of  the  Ben  Davis  were  affected.  The  interval  of  five  weeks 


112 


BULLETIN  No.  185 


[February, 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  113 

between  the  third  and  fourth  applications  was  too  long  to  control  it 
with  this  fungicide  in  this  variety. 

The  treatment  which  seems  to  be  of  the  most  value  when  russet 
and  foliage  injury  are  considered,  includes  the  use  of  lime  sulfur  for 
the  applications  following  the  fall  of  the  petals,  up  to  the  time  when 
the  danger  of  Bordeaux  russet  is  past.  Plats  2,  3,  4,  and  10  were 
treated  in  that  manner,  the  fourth  application,  as  stated,  being  Bor- 
deaux. The  amount  of  blotch  on  these  plats  ran  between  0  on  the 
lowest  Jonathan  plats  to  7.5  percent  on  the  highest  Ben  Davis  plat, 
the  greater  amount  being  uniformly  on  the  Ben  Davis.  Considering 
the  comparative  freedom  from  blotch  on  plats  sprayed  in  this  manner, 
and  the  long  interval  between  the  third  and  fourth  applications,  when 
infection  on  the  Ben  Davis  apples  was  taking  place,  an  extra  appli- 
cation of  lime  sulfur  arsenate  of  lead,  to  be  made  between  what  were 
this  year  the  third  and  fourth  applications,  and  coming  about  the 
middle  of  June,  would  apparently  have  afforded  complete  protection. 

Sooty  Blotch  and  Flyspeck. — Sooty  blotch  and  flyspeck  appear  in 
the  latter  part  of  the  summer,  and  as  it  is  found  that  a  treatment 
which  will  control  one  will  control  the  other,  they  are  considered  to- 
gether. 

Sooty  blotch  was  first  observed  during  this  season  August  3.  Altho 
the  final  spray  was  applied  almost  a  month  before  the  appearance  of 
this  fungus,  both  sooty  blotch  and  flyspeck  were  controlled  on  all  the 
Jonathan  plats  with  the  exception  of  1.3  percent  of  sooty  blotch 
on  Plat  10  (Bordeaux,  lime  sulfur,  lime  sulfur,  Bordeaux),  and 
between  1.2  and  5.6  percent  on  Plat  13  (copper  ferrocyanide  alone). 

Russet. — Heavy  rains  followed  the  second,  third,  and  fourth  appli- 
cations. The  weather  was  favorable  for  the  formation  of  russet,1  an 
average  of  28.7  percent  of  the  apples  from  the  Ben  Davis  check  plats 
and  18.6  percent  from  the  Jonathan  check  plats  being  severely  af- 
fected. 

Two  kinds  of  russet  were  observed  on  the  apples  from  the  sprayed 
plats.  The  most  noticeable  kind  consisted  in  a  more  or  less  extensive 
corky  surface,  which,  when  extensive  or  rough  enough  to  throw  the 
individual  apples  into  the  cull  grade,  is  given  in  the  table  as  ''severe 
russet.'1'  It  is  desirable  to  avoid  this  form  of  russet  entirely  if  possi- 
ble, because,  even  if  the  individual  apples  are  not  severely  russeted, 
the  presence  of  a  slight  amount  greatly  detracts  from  the  appear- 
ance of  a  barrel  or  a  box  of  the  fruit.  A  black  dotting  constituted  an- 
other form  of  russeting.  It  was  scarcely  noticeable  at  picking  time, 
altho  in  the  early  part  of  the  season  this  form  of  injury  looked  serious. 
Up  to  the  time  of  the  fourth  application,  it  was  confined  to  the  plats 
which  had  received  the  second  or  third  application  of  Bordeaux.  After 
the  fourth  application  (Bordeaux  or  copper  ferrocyanide)  it  devel- 
oped on  all  the  plats. 

'Hedrick,  U.  P.,  N.  Y.  (Geneva)  Agr.  Exp.  Sta.  Bui.  287,  pp.  166-169. 


114  BULLETIN  No.  185  [February, 

The  amount  of  russet  varied  with  the  treatment,  russet  following 
the  use  of  Bordeaux  when  used  for  any  of  the  applications.  On  Plat  4, 
where  lime  sulfur  and  Grasselli  arsenate  of  lead  were  used  for  the  first 
three  applications  and  Bordeaux  and  Grasselli  arsenate  of  lead  for  the 
fourth,  there  was  3.5  percent  severe  russet  on  the  Jonathans  and  13.3 
percent  on  the  Ben  Davis.  On  the  other  hand,  Bordeaux  and  Grasselli 
arsenate  of  lead,  when  used  for  all  four  applications  (Plat  8),  gave 
88.6  percent  severe  russet  on  the  Jonathans  and  74.3  percent  on  the 
Ben  Davis.  The  crop  from  this  plat  was  practically  ruined  for  boxing 
or  even  barreling  purposes. 

A  question  of  great  importance  is  the  amount  of  russet  caused  by 
each  of  the  first  three  applications  of  Bordeaux.  In  order  to  estimate 
this  roughly,  Plat  4  is  again  taken  as  a  standard  for  comparison  with 
plats  on  which  more  Bordeaux  was  used  (Plats  5  to  11).  Plat  4  re- 
ceived, as  stated  in  the  preceding  paragraph,  lime  sulfur  and  Grasselli 
arsenate  of  lead  for  the  first  three  applications  and  Bordeaux  and 
Grasselli  arsenate  of  lead  for  the  fourth.  Plats  5  to  11  received  Bor- 
deaux for  the  fourth,  and  Bordeaux  instead  of  lime  sulfur  for  one  or 
more  of  the  first  three  applications,  with  the  same  arsenate  of  lead  as 
Plat  4.  The  comparison  can  be  studied  readily  in  Table  22.  The  fig- 
ures represent  the  increase  in  percentage  of  apples  showing  severe  rus- 
set over  that  found  on  the  Jonathans  (3.5  percent)  and  the  Ben  Davis 
(13.3  percent)  from  Plat  4. 

TABLE  22. — PERCENTAGE  INCREASE  OVER  PLAT  4  IN  SEVERE  EUSSET  AS  A  HESULT 

OP  USING  BORDEAUX  FOR  APPLICATIONS  BEFORE  THE  FOURTH  IN  THE 

EXPERIMENTS  AT  FLORA,  1912 


Plat 

Applications 
of  Bordeaux 

Jonathan 

Ben  Davis 

10 

.1,     4 

10.3 

11.5 

6 

—       2,  —    4 

38.6 

9.6 

5 

3,   4 

28.2 

75.6 

9 

1,         2,   --    4 

76.1 

38.2 

7 

--       2,       3,   4 

84.8 

.... 

11 

1,     --       3,   4 

49.8 

37.6 

8 

1,         2,       3,   4 

85.1 

61.0 

NOTE. — Dashes  under  the  heading  Applications  of  Bordeaux  signify  the  use  of 
lime  sulfur. 

It  will  be  seen  that  the  first  application  of  Bordeaux  in  place  of 
lime  sulfur  (Plat  10)  increased  the  severe  russet  on  the  Jonathans 
10.3  percent;  the  second  application  increased  it  38.6  percent  (Plat 
6)  ;  and  the  third  increased  it  28.2  percent  (Plat  5),  the  third  applica- 
tion being  less  harmful  on  this  variety  than  the  second. 

The  Ben  Davis  apples,  which  were  sprayed  at  all  times  in  exactly 
the  same  way  and  at  the  same  time  as  the  Jonathans,  did  not  shoAv  like 
results  except  for  the  first  application  (Plat  10),  which  gave  an  in- 
crease over  Plat  4  of  11.5  percent  in  the  severely  russeted  fruit.  The 
second  application  (Plat  6)  gave  only  9.6  percent  increase,  while  the 
third  (Plat  5)  gave  the  great  increase  of  75.6  percent. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  US 

Combinations  of  any  two  of  the  applications  gave  very  severe  in- 
jury. For  example,  the  first  and  third  applications  of  Bordeaux  (Plat 
11)  gave  an  increase  of  49.8  percent  severely  russeted  Jonathans  and 

37.6  percent  severely  russeted  Ben  Davis.  These  percentages  correspond 
with  a  total  of  53.3  percent  for  the  Jonathans  and  50.9  percent  for  the 
Ben  Davis,  and  mean  that  the  use  of  Bordeaux  just  before  the  bloom 
and  for  the  application  three  to  four  weeks  after  the  petals  fell  re- 
sulted in  the  culling  of  one  half  of  the  crop  on  account  of  russet. 

A  point  of  great  interest  is  the  fact  that  the  apples  from  the  plats 
sprayed  the  first  three  times  with  lime  sulfur  and  Grasselli  arsenate 
of  lead,  and  the  fourth  time  with  Bordeaux  and  Grasselli  arsenate  of 
lead,  showed  much  less  severe  russet  than  the  apples  from  the  check 
plats.  While  the  average  severe  russet  for  the  Jonathan  check  plats 
was  18.6  percent  and  for  the  Ben  Davis  check  plats  28.7  percent,  only 
3.5  percent  of  the  Jonathans  and  13.3  percent  of  the  Ben  Davis  from 
Plat  4,  which  received  the  treatment  specified  above,  showed  severe  rus- 
set. The  reduction  was  approximately  15  percent  on  both  varieties. 
The  freedom  from  severe  russet  was  accompanied  by  a  smoother  and 
higher  finish  than  was  shown  by  the  apples  from  the  checks.  This  dif- 
ference in  ' '  finish ' '  is  not  shown  in  the  table. 

Altho  lime  sulfur  and  Grasselli  arsenate  of  lead  were  of  value  in 
lessening  the  amount  of  russet  and  in  causing  an  improvement  of  the 
finish,  Hemingway  and  Sherwin-Williams  arsenate  of  lead  did  not 
show  as  good  results,  possibly  largely  because  of  weather  conditions.  In 
treatments  similar  to  that  given  Plat  4,  but  where  Hemingway  or 
Sherwin-Williams  arsenates  of  lead  were  used  instead  of  Grasselli, 
Sherwin-Williams  arsenate  of  lead  (together  with  the  fungicide) 
showed,  on  Plat  3,  10.5  percent  of  severe  russet  on  the  Jonathan  and 

27.7  percent  on  the  Ben  Davis.    These  amounts  agreed  closely  with  the 
amounts  shown  on  the  checks.     Hemingway  arsenate  of  lead,  when 
used  instead  of  Grasselli  (Plat  2),  gave  somewhat  better  results  than 
the  Sherwiii- Williams  product,  the  amount  of  severe  russet  on  the  Ben 
Davis  apples  being  reduced  to  19.4  percent,  which  is  9.3  percent  less 
than  that  shown  on  the  checks.     Plat  4  was  always  sprayed  two  or 
three  days  sooner  than  Plats  2  and  3,  and  since  a  heavy  fall  of  rain 
occurred  a  day  or  two  after  Plat  4  was  sprayed  the  second,  third,  and 
fourth  times,  before  Plats  2  and  3  were  sprayed,  a  strict  comparison 
of  the  treatments  given  these  three  plats  is  prevented. 

The  active  f ungicidal  principle  of  Bordeaux  is  copper ;  and  it  was 
thought  that  an  excess  of  soluble  copper,  above  that  necessary  to  pro- 
tect foliage  from  fungous  infection,  was  responsible  for  Bordeaux  in- 
jury. Two  other  copper  compounds  beside  Bordeaux  were  therefore 
tried, — copper  ferrocyanide,  and  the  compound  resulting  from  the  ad- 
dition of  copper  sulfate  to  lime  sulfur.  The  spray  sought  was  one 
which  would  be  just  soluble  enough  to  liberate  sufficient  copper  to  pre- 
vent fungous  infection,  but  no  more.  Altho  a  smaller  amount  of  rus- 


116  BULLETIN  No.  185  [February, 

set  resulted  this  year  from  the  first  application  of  Bordeaux  than  from 
the  second  or  third,  the  compound  of  copper  sulfate  and  lime  sulfur 
gave  a  large  amount  of  russet  even  when  used  for  the  first  application, 
which  might  be  expected  to  be  the  safest  of  all  three  from  the  stand- 
point of  copper  injury.  On  the  plat  on  which  it  was  used  (Plat  14), 
27.6  percent  of  the  Jonathans  were  severely  russeted,  13.8  percent 
more  injury  than  the  similar  Bordeaux  plat  showed  (Plat  10),  and  an 
increase  of  24.1  percent  over  that  shown  by  Plat  4,  the  similar  lime- 
sulfur  plat.  Weather  conditions  at  the  time  of  the  first  application 
allow  a  comparison  between  the  two  plats.  Plat  4  was  sprayed  April 
23,  and  Plat  14,  April  24.  Both  days  were  clear,  with  a  moderate  wind 
suitable  for  drying  the  spray  on  the  foliage.  April  25  was  cloudy,  and 
during  the  night  of  April  25-26  there  were  1.27  inches  of  rain.  Be- 
cause of  the  severe  russet  resulting  from  the  use  of  this  spray,  it  does 
not  seem  probable  that  it  will  be  found  of  value. 

Copper  f  errocyanide,  the  other  copper  compound  which  was  tried 
in  the  effort  to  find  a  suitable  copper  spray,  gave  more  russet  than 
would  have  been  expected  in  view  of  its  very  low  solubility  in  water, 
its  comparatively  low  fungicidal  power,  and  the  freedom  of  the  plats 
sprayed  with  it  from  foliage  injury.  Less  injury  was  occasioned  by 
its  use  alone  (Plat  13)  than  by  its  use  in  combination  with  arsenate  of 
lead  (Plat  12).  By  its  use  with  arsenate  of  lead  57  percent  of  the 
Ben  Davis  apples,  and  36  percent  of  the  Jonathans  were  severely 
russeted. 

It  is  unfortunate  that  so  few  apples  were  harvested  from  Plat  1, 
the  plat  on  which  lead  acetate  and  lime  sulfur  was  used,  that  no  rec- 
ords could  be  taken.  The  unstable  lead  and  sulfur  compound  formed 
when  lead  acetate  is  added  to  lime  sulfur  may  be  a  valuable  fungicide, 
and,  because  of  its  insolubility,  may  be  expected  to  cause  but  little 
injury. 

SUMMARY  OF  RESULTS  AT  FLORA,  1912 
FOLIAGE 

The  effects  of  the  sprays  on  the  foliage  may  be  summarized  as  fol- 
lows: 

1.  Lime  sulfur  arsenate  of  lead  caused  no  foliage  injury. 

2.  Bordeaux  arsenate  of  lead  caused  severe  injury  as  a  result 
of  the  second,  third,  and  fourth  applications,  but  not  as  a  result  of  the 
first  application. 

3.  Copper  f  errocyanide  alone  and  with  arsenate  of  lead  caused 
no  serious  foliage  injury. 

4.  Copper  sulfate  and  lime  sulfur  arsenate  of  lead,  used  for  the 
first  application,  caused  no  foliage  injury. 

5.  Lead  acetate  did  not  materially  change  the  properties  of  lime 
sulfur  arsenate  of  lead,  so  far  as  could  be  observed  this  year.     The 
spray  was  black  at  first,  but  soon  lost  its  distinctive  color. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  117 

6.  There  was  practically  no  scab  on  the  foliage.    Its  absence  may 
be  responsible,  in  part  at  least,  for  the  absence  of  lime-sulfur  injury 
and,  together  with  the  vigorous  condition  of  the  trees,  for  the  late  ap- 
pearance of  Bordeaux  injury. 

7.  Leaf  spot  caused  the  check  Ben  Davis  trees  to  lose  the  most  of 
their  foliage  during  September.    It  was  not  so  severe  on  the  Jona- 
thans. All  of  the  fungicides  used  afforded  protection  from  this  fungus. 

8.  The  apple  flea-weevil  was  not  controlled  by  the  sprays  used. 

FEUIT 

Scab. — There  was  no  scab  on  the  Jonathans.  The  slight  amount 
on  the  Ben  Davis  was  controlled  by  all  the  sprays. 

Blotcli. — The  outbreak  of  blotch  was  severe.  Lime  sulfur,  used  for 
the  third  application,  with  Bordeaux  for  the  fourth,  was  not  quite  as 
efficient  as  Bordeaux  used  for  both  the  third  and  fourth  applications 
in  the  control  of  blotch  on  the  Ben  Davis,  but,  with  the  exception  of  one 
plat,  was  as  efficient  in  controlling  it  on  the  Jonathans.  The  in- 
terval between  the  third  and  fourth  applications  was  between 
four  and  five  weeks,  during  which  time  there  was  severe  infection  of 
the  Ben  Davis  checks,  altho  none  appeared  on  the  Jonathan  checks 
until  about  two  weeks  after  the  fourth  application.  It  seems  probable 
that  an  extra  application  of  lime  sulfur,  coming  between  what  were 
the  third  and  fourth  applications,  would  have  given  complete,  or  al- 
most complete,  protection.  Copper  ferrocyanide  allowed  a  slight  in- 
fection of  the  Jonathans  and  afforded  some  protection  to  the  Ben 
Davis.  Copper  ferrocyanide  and  arsenate  of  lead  controlled  the  blotch 
on  the  Jonathans  and  afforded  more  protection  on  the  Ben  Davis.  The 
long  interval  between  the  third  and  fourth  applications,  and  the  ap- 
pearance of  blotch  before  the  fourth  application  on  the  Ben  Davis, 
may  again  account  for  the  difference  in  the  control  of  blotch  on  the 
two  varieties. 

Sooty  Blotch  and  Flyspeck. — Altho  the  infection  on  the  checks  was 
severe  these  fungi  were  controlled  on  the  plats  sprayed  with  Bordeaux 
between  July  1  and  5.  Copper  ferrocyanide  and  arsenate  of  lead  ap- 
plied at  that  time  gave  perfect  control,  but  there  was  a  small  amount 
on  both  varieties  where  copper  ferrocyanide  was  used  alone. 

Russet. — Severe  russeting  resulted  on  both  varieties  from  the  use 
of  Bordeaux  arsenate  of  lead  for  the  first,  second,  and  third  applica- 
tions. Another  form  of  injury,  consisting  in  a  black  dotting,  resulted 
from  the  second,  third,  and  fourth  applications.  At  picking  time,  how- 
ever, this  was  almost  negligible.  Copper  ferrocyanide,  and  the  copper- 
sulfate  and  lime-sulfur  mixture  caused  severe  russeting,  copper  ferro- 
cyanide causing  more  when  used  with  arsenate  of  lead  than  when  used 
without.  Lime  sulfur  was  of  benefit  in  preventing  russet  and  in  im- 
proving the  finish  of  the  apples  of  both  varieties. 


118  BULLETIN  No.  185  [February, 


SPRAYING  EXPERIMENTS  IN  1909  AT  GRIGGSVILLE, 
PIKE  COUNTY 

BY  L.  EARL  FOGLESONG,  ASSISTANT  IN  POMOLOGY 
OBJECTS 

Spraying  experiments  were  conducted  in  the  season  of  1909  near 
Griggsville,  in  order  to  ascertain  the  relative  efficiency  of  various  com- 
mercial and  homemade  sprays  in  preventing  or  controlling  insects  and 
fungous  diseases. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

An  orchard  belonging  to  Mr.  John  Sawdon,  located  two  miles 
south  of  Griggsville,  which  had  been  used  in  1904  and  1906  by  the 
Department  of  Horticulture,  was  selected  for  these  tests.  As  there 
were  not  sufficient  Ben  Davis  trees  on  which  to  run  all  the  series,  some 
trees  of  the  Milam  variety  were  used. 

TREATMENT 

The  plats  were  sprayed  with  various  insecticides  and  fungicides  as 
shown  in  Tables  23  to  27.  In  all  the  series,  except  the  one  where 
the  number  of  sprays  was  varied,  five  applications  were  made  on  or 
near  the  following  dates : 

First  application:  just  before  bloom,  April  27,  May  3 

Second  application:  within  ten  days  after  fall  of  bloom,  May  11-14 

Third  application:  ten  days  later,  May  21-27 

Fourth  application:  June  24-29 

Fifth  application:  July  14-16 

All  the  plats  in  each  series  were  sprayed  the  same  day  and  as 
nearly  under  the  same  conditions  of  weather  as  possible,  so  that  the 
data  collected  from  leaf  and  fruit  examinations  would  be  comparable. 

CHARACTER   OF  RECORDS  AND  METHOD  OF   MAKING 

The  fruit  from  each  tree  of  the  various  experiments  was  examined 
carefully  and  recorded  at  the  time  of  harvesting,  and  general  notes 
were  taken  on  the  foliage  from  time  to  time  thruout  the  summer.  In 
the  following  tables,  the  percentages  of  apples  injured  by  apple 
scab,  curculio,  russeting,  and  codling  moth  are  given.  As  a  total  of 
only  four  or  five  apples  were  found  with  blotch,  and  but  two  with  bit- 
ter rot,  fruit  affected  by  these  diseases  is  not  reported  in  the  tables. 

COMPARISON  OF  VARIOUS  BRANDS  OF  ARSENATE  OF  LEAD 
AND  PARIS  GREEN 

The  treatments  used  in  Group  1,  together  with  the  fruit  data  re- 
corded, are  given  in  Table  23. 


1916} 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


119 


oooooo 
o  © 


§OO 
©  O@OOO 

oo@o® 


'Ben  Davis  Wealthy 

CHABT  6. — PLAN  OF  PLATS  IN  ORCHARD  OP  MR.  JOHN  SAWDON,  GRIGGSVILLE,  1909 


120 


BULLETIN  No.  185 


TABLE  23. — EFFECTS  OF  SPRAYING  WITH  VARIOUS  BRANDS  AND  STRENGTHS  OF  AR- 
SENATE  OF  LEAD  AND  PARIS  GREEN,  IN  THE  EXPERIMENTS  AT  GRIGGSVILLE,  1909 


Plat 

Trees 

Treatment 

Percentage  picked 
apples  affected  by 

3 

<a 
00 

«),a 
•So 

1* 

o 

Curculio 

Check 
1 

2 
4 
5 
6 

Check 

8 

9 

10 

1 
2-3 

4-5 
8-9 
10-11 
13-14 

12 
17-18 

19-20 
21-22 

No  treatment  

99 

88 
92 
90 
95 

89 
89 

94 
97 
90 

12 
0 
0 
0 
1 

0 
5 

1 
0 
1 

98 
67 

65 
68 

77 

63 
81 

96 
78 
85 

Grasselli  arsenate  of  lead,  6  Ibs.  to  300  gals, 
water  

Grasselli  arsenate  of  lead,  4  Ibs.  to  100  gals, 
water  

Target  brand  arsenate  of  lead,  6  Ibs.  to   100 
gals,  water  

Sherwin-Williams  arsenate  of  lead,  6  Ibs.  to  100 
gals,  water  

Homemade  arsenate  of  lead,  2  Ibs.  to  100  gals, 
water  

No  treatment  

Sherwin-Williams   Paris   green,    %    lb.,   lime   2 
Ibs.,  to  100  gals,  water  

Ansbacher  Paris  green,  %  lb.,  lime  2  Ibs.,  to  100 
gals,  water  

Paris  green,  equivalent  to  arsenate  of  lead  in 
Plat  5  . 

EFFECT  ON   FRUIT 

Scab. — Neither  arsenate  of  lead  nor  Paris  green  in  any  of  the 
brands  or  forms  used  showed  any  effect  in  the  control  of  scab. 

Codling  Moth. — All  brands  of  arsenate  of  lead  and  Paris  green 
showed  excellent  control  of  codling  moth. 

Curculio. — Arsenate  of  lead  in  all  forms  reduced  the  percentage 
of  curculio  injury  by  amounts  ranging  from  4  to  35  percent  (Plat  5 
as  compared  with  Check  Tree  12,  and  Plat  6  compared  with  Check 
Tree  1).  The  average  reduction  in  curculio  injury  for  the  arsenate  of 
lead  plats  (Plats  1,  2,  4,  5,  and  6)  was  22  percent,  as  compared  with 
the  average  of  two  check  trees  (Plats  1  and  12).  The  trees  sprayed 
with  Paris  green  showed  no  consistent  reduction  of  curculio  injury  as 
a  result  of  spraying. 

Six  pounds  of  arsenate  of  lead  per  100  gallons  of  spray  mixture 
were  not  more  effective  than  4  pounds  per  100  gallons  in  controlling 
codling  moth  and  curculio. 

Homemade  arsenate  of  lead  proved  more  efficient,  if  anything,  than 
the  commercial  product,  but  the  results  were  not  sufficiently  different 
to  recommend  its  adoption  over  the  commercial  arsenate  of  lead. 

EFFECT  ON  FOLIAGE 

Arsenate  of  lead  caused  no  foliage  injury,  but  the  foliage  of  the 
trees  in  Plats  8  and  10,  where  Sherwin-Williams  Paris  green  was  used, 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


121 


was  severely  burned.  The  foliage  of  Plat  9,  sprayed  with  Ansbacher 
Paris  green,  was  much  less  severely  burned,  tho  some  injury  occurred 
in  this  plat  late  in  the  season  following  the  fifth  application.  The 
foliage  on  Plats  8  and  10  was  so  severely  injured  as  to  reduce  the  size 
of  the  fruit  noticeably.  Plat  10,  which  suffered  the  most,  even  pro- 
duced a  second  crop  of  leaves  late  in  the  season  in  an  effort  to  replace 
foliage  lost  by  spray  injury. 

COMPARISONS  OF  COMMERCIAL  AND  SELF-BOILED  LIME  SULFUR 
WITH  AND  WITHOUT  ARSENICAL  INSECTICIDES 

The  treatments  used  in  Group  2,  together  with  the  fruit  data  re- 
corded, are  given  in  Table  24. 

TABLE  24. — EFFECTS  OF  COMMERCIAL  AND  SELF-BOILED  LIME  SULFUR  WITH  AND 
WITHOUT  ARSENICAL  INSECTICIDES,  IN  THE  EXPERIMENTS  AT  GRIGGSVILLE,  1909 


Plat 

Trees 

Treatment 

Percentage  picked 
apples  affected  by 

£> 

60  « 
•if 

•§s 

u 

.2 

13 

B 

G 

0 

o 

11 
12 
13 

Check 
14 
15 
16 

17 

Check 

23-24 
25-26 
27-28 
29 
30-31 
32-33 
34-35 
37-38 

36 

Lime  sulfur,  commercial,  with  Paris  green  

53 
39 

72 
95 

89 

87 
87 

85 
89 

4 
25 
4 
11 

22 
18 
30 

1 
13 

84 
72 
73 
97 
91 
84 
75 

78 
91 

Lime  sulfur,  commercial,  alone  

Lime  sulfur,  commercial,  with  arsenate  of  lead 
No  treatment  

Lime  sulfur,  self  -boiled,  12—12—100,  alone  

Lime  sulfur,  self  -boiled,  16-16-100,  alone  
Lime  sulfur,  self  -boiled,  20-20-100,  alone  

Lime  sulfur,  self-boiled,  16-16—100,  with  arsen- 
ate of  lead  

No  treatment  . 

EFFECT   ON  FRUIT 

Scab. — The  applications  of  commercial  lime  sulfur  made  on  Plats 
11,  12,  and  13,  reduced  scab  on  an  average  by  37  percent  as  compared 
with  the  average  in  the  check  plats.  Most  of  the  scab  on  the  sprayed 
plats  was  of  so  light  a  nature  as  would  not  readily  be  noticed,  occur- 
ring largely  in  the  form  of  an  early  attack  of  the  disease  which  did 
not  disfigure  the  apples  at  picking  time.  The  disfiguring  marks  of 
scab  were  largely  confined  to  the  untreated  apples.  The  spray  was 
therefore  much  more  effective  than  the  figures  in  the  table  indicate. 
The  self-boiled  lime  sulfur  showed  little  value  in  preventing  attacks  of 
scab,  the  average  scab  infection  for  the  self-boiled  lime-sulfur  plats 
being  87  percent,  as  compared  with  92  percent,  the  average  on  the 
unsprayed  trees. 

Codling  Moth. — Both  Paris  green  and  arsenate  of  lead  exercised  a 
most  satisfactory  control  of  this  insect  in  every  case.  There  was  an 


122  BULLETIN  No.  185  [February, 

average  infestation  of  4  percent  on  the  plat  sprayed  with  Paris  green 
(Plat  11)  and  of  2.5  percent  on  the  plats  sprayed  with  arsenate  of 
lead  (Plats  13  and  17),  compared  with  an  average  of  12  percent  on 
the  untreated  trees.  Codling  moth  was  evidently  rather  strongly  at- 
tracted to  the  trees  sprayed  with  lime  sulfur ;  the  fruit  on  these  trees 
was  more  severely  attacked  by  this  insect  than  the  fruit  on  the  un- 
sprayed  trees,  a  difference  that  held  consistently  for  all  the  plats 
sprayed  with  lime  sulfur  alone  (Plats  12,  14,  15,  and  16),  which 
showed  an  average  codling-moth  infestation  of  24  percent,  or  double 
the  average  infestation  of  the  unsprayed  trees. 

Curculio. — The  differences  in  curculio  infestation  between  the 
treated  plats  were  not  consistent,  but  with  the  exception  of  Plat  14,  all 
sprayed  trees  indicated  some  degree  of  control  by  the  treatments,  as 
compared  with  the  untreated  plats. 

Even  Plat  1.4,  sprayed  with  self -boiled  lime  sulfur  (12-12-100) 
alone,  showed  3  percent  less  curculio  injury  than  the  average  of  the 
check  plats.  The  addition  of  arsenate  of  lead  and  of  Paris  green  to 
lime  sulfur  did  not  aid  noticeably  in  controlling  curculio,  the  average 
infestation  in  the  plats  where  the  poisons  were  used  being  78  percent, 
as  compared  with  80.5  percent  for  the  plats  sprayed  with  lime  sulfur 
alone.  Contrary  to  the  experience  in  the  control  of  codling  moth,  lime 
sulfur  appeared  to  exercise  a  repellent  effect  on  the  curculio.  Plats 
sprayed  with  lime  sulfur  alone  (Plats  12,  14,  15,  and  16)  showed  an 
average  infestation  of  80.5  percent,  as  compared  to  an  average  infes- 
tation on  the  unsprayed  trees  of  94  percent. 

Self -boiled  lime  sulfur  proved  to  be  an  inefficient  fungicide.  Lime 
sulfur  (commercial)  showed  considerable  fungicidal  value. 

EFFECT  ON  FOLIAGE 

The  foliage  was  good  thruout  this  group,  but  was  perhaps  slightly 
better  in  Plats  13  and  17,  where  arsenate  of  lead  was  added  to  the 
fungicide,  than  in  the  other  plats  in  the  series.  There  were  no  rus- 
seted  apples  in  the  plats  in  this  group. 

COMPARATIVE  EFFECTIVENESS  OF  SPRAYING  ONCE  BEFORE 
THE  BLOOM  AND  SPRAYING  ONCE  AFTER  THE  BLOOM 

The  treatments  used  in  Group  3,  together  with  the  fruit  data  re- 
corded, are  given  in  Table  25. 

EFFECT  ON  FRUIT 

Scab. — In  1909  the  spray  which  followed  the  fall  of  the  petals  was 
more  effective  in  controlling  scab  than  the  spray  which  preceded  the 
bloom. 

Codling  Moth. — As  was  to  be  expected,  the  spray  which  followed 
the  fall  of  the  petals  was  more  efficient  in  reducing  codling-moth  in- 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


123 


jury  than  the  spray  which  preceded  bloom.  The  noteworthy  point  in 
regard  to  this  treatment  was  the  effectiveness  of  the  one  application, 
only  3  percent  of  the  apples  in  Plat  21  (sprayed  after  the  fall  of  the 
petals)  being  injured  by  codling  moth,  as  compared  with  17  percent 
on  the  check  plat. 

TABLE  25. — EFFECTS  OF  INDIVIDUAL  APPLICATIONS  BEFORE  AND  AFTER  THE  BLOOM, 

USING  BORDEAUX  IN  COMBINATION  WITH  ARSENATE  OF  LEAD,  IN  THE 

EXPERIMENTS  AT  GRIGGSVILLE,  1909 


Plat 

Trees 

Treatment 

Percentage  of  picked 
apples  affected  by 

1 

QO 

&c  - 

s73 
~  o 

1« 

O 

Curculio 

-fa 
• 
• 

m 

S 

03 

Check 
20 
21 

41 

44-45 
46-47 

No  treatment  

89 
85 
49 

17 
12 
3 

83 

88 
87 

0 
1 
23 

Sprayed  before  bloom  

Sprayed  just  after  fall  of  petals  

Curculio. — Both  applications  were  evidently  too  early  to  exercise 
any  control  over  the  curculio. 

Russet. — Practically  no  russeting  resulted  from  the  application 
preceding  the  bloom.  As  a  result  of  the  application  following  the 
fall  of  the  petals,  23  percent  of  the  apples  were  more  or  less  russeted. 

EFFECT  ON  FOLIAGE 

Cankerworms  appeared  in  the  orchard  just  as  the  leaf  buds  were 
expanding,  but  were  completely  checked  by  the  application  preceding 
the  bloom. 

COMPARATIVE  EFFECTIVENESS  OF  BORDEAUX  WITH  AND 
WITHOUT  ARSENICAL  INSECTICIDES 

The  treatments  used  in  Group  4,  together  with  the  fruit  data  re- 
corded, are  given  in  Table  26. 

EFFECT  ON  FRUIT 

Scab. — This  disease  was  immensely  reduced  in  all  the  sprayed 
plats,  the  average  reduction  of  the  infection  amounting  to  52  percent. 
Bordeaux  alone  appeared  to  exercise  a  better  control  of  scab  than  the 
combined  Bordeaux  and  arseriate  of  lead  or  the  combined  Bordeaux 
and  Paris  green,  as  may  be  seen  by  comparing  Plat  25  with  Plats  35, 
36,  and  37.  This  idiosyncracy,  in  the  light  of  other  results,  must  be 
attributed  to  seasonal  conditions  or  experimental  error. 

Codling  Mofh. — The  addition  of  poisons  to  the  Bordeaux  reduced 
the  injury  from  codling  moth  to  an  average  of  4  percent  (Plats  35, 
36,  and  37),  as  compared  with  an  injury  of  20  percent  on  the  check 


124 


BULLETIN  No.  185 


[February, 


TABLE  26. — EFFECT  OF  BORDEAUX  WITH  AND  WITHOUT  ARSENICAL  INSECTICIDES, 
IN  THE  EXPERIMENTS  AT  GRIGOSVILLE,  1909 


Plat 

Trees 

Treatment 

Percentage  picked 
apples  affected  by 

a 

OQ 

"•<    o 

1* 
O 

Curculio 

25 
35 

36 

37 
Check 

61-62 
83-84 

85-86 

87-88 
89 

Bordeaux  alone   

7 
16 

13 
11 
63 

15 

1 

3 

8 
20 

77 
63 

68 
82 
93 

Bordeaux  with  arsenate  of  lead,  6  Ibs.  to  100 
srals. 

Bordeaux  with  arsenate  of  lead,  4  Ibs.  to  100 
srals. 

Bordeaux  with  Paris  green,  %  lb.  to  100  gals. 
No  treatment  . 

trees  and  15  percent  on  trees  sprayed  with  Bordeaux  alone.  Arsenate 
of  lead  proved  more  effective  than  Paris  green,  reducing  the  injury  to 
an  average  of  2  percent  (Plats  35  and  36)  as  compared  with  8  percent 
on  the  trees  sprayed  with  Paris  green  (Plat  37). 

Curculio. — As  compared  with  the  check,  where  the  curculio  infes- 
tation amounted  to  93  percent,  the  injury  in  the  plats  where  arsenate 
of  lead  was  used  was  reduced  to  an  average  of  65  percent  and  in  the 
plat  where  Paris  green  was  used  to  82  percent.  There  was  less  cur- 
culio damage  even  in  the  plat  where  Bordeaux  was  used  alone  than  in 
the  check  plat. 

EFFECT  ON  FOLIAGE 

More  foliage  injury  occurred  in  Plat  37,  sprayed  with  Paris  green, 
than  in  the  plats  sprayed  with  arsenate  of  lead. 

COMPARISON  OF  MISCELLANEOUS  SPRAYS 

The  treatments  used  in  Group  5,  together  with  the  fruit  data  re- 
corded, are  given  in  Table  27. 

EFFECT  ON  FRUIT 

Scab. — Homemade  Bordeaux  and  Target  brand  Bordeaux  were 
equally  efficient  in  controlling  scab.  Bordeaux  made  with  carefully 
slaked  lime  showed  no  superiority  over  Bordeaux  made  with  care- 
lessly slaked  lime  in  lessening  injury  from  this  disease.  The  addition 
of  iron  sulfate  to  Bordeaux,  which  was  added  only  to  improve  the  ad- 
hesive qualities  of  the  spray,  did  not  increase  the  fungicidal  value  of 
the  mixture.  All  sprays  exercised  a  large  degree  of  control  over  scab. 

Codling  Moth. — Arsenate  of  lead,  used  thruout  the  group,  reduced 
the  amount  of  codling-moth  injury  satisfactorily  except  in  Plat  42, 
where  iron  sulfate  was  added  to  the  spray.  Infection  in  this  plat,  how- 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


125 


TABLE  27. — EFFECTS  OF  MISCELLANEOUS   PREPARATIONS,   IN   THE   EXPERIMENTS 

AT  GRIGGSVILLE,  1909 


Plat 

Trees 

Treatment 

Percentage  of  picked 
apples  affected  by 

fi 

2* 

^H      0 

-§a 
o 

Curculio 

1 

03 

B 

1 

26 

27 

Check 
29 

30 

40 
42 

Check 

63-61 
65-66 

67 

70-71 

72-73 

94-95 
99-100 

98 

Homemade    Bordeaux   with    arsenate    of 
lead    

10 

9 
53 

11 

8 
26 

32 
51 

2 

3 

12 

3 

1 
2 

8 
19 

57 

49 

78 

72 

64 

84 

89 
99 

52 

42 
3 

59 

44 
50 

26 
1 

Target  brand  quick  Bordeaux  with  arsen- 
ate of  lead  

No  treatment  

Bordeaux  made  with  carefully  slaked  lime 
with  arsenate  of  lead  

Bordeaux    made    with    carelessly    slaked 
lime  with  arsenate  of  lead  

Bordeaux  with  arsenate  of  lead  

Bordeaux  with  iron  sulfate  with  arsenate 
of  lead    

No  treatment  . 

ever,  as  shown  by  the  corresponding  checks,  was  higher  than  in  the 
other  plats  included  in  the  group.  It  cannot  be  concluded,  therefore, 
that  iron  sulfate  lessened  the  efficiency  of  the  arsenate  of  lead. 


126 


BULLETIN  No.  185 


SPRAYING  EXPERIMENTS  IN  1910  AT  CENTRALIA, 
MARION  COUNTY 

BY  L.  EAEL  FOGLESONG 


OBJECTS 

The  objects  of  the  experiments  at  Centralia  in  1910  were  to  study : 
(1)  the  efficiency  of  Bordeaux  and  lime  sulfur  as  fungicides;  (2)  the 
efficiency  of  homemade,  commercial,  and  self -boiled  lime  sulfur  for  late 
spring  and  summer  sprays;  (3)  the  effects  of  adding  lime-sulfur  sludge 
to  the  clear  solution;  (4)  the  effects  of  using  various  proportions  of 
lime  and  sulfur  in  making  the  self -boiled  product;  and  (5)  the  rela- 
tive values  of  acid,  neutral,  and  mixed  arsenates  of  lead. 

LOCATION  AND  DESCRIPTION   OF  ORCHARD 

It  was  planned  to  carry  out  experiments  bearing  on  the  above  ques- 
tions in  several  orchards — one  each  in  Pike,  Calhoun,  Cumberland, 
Clay,  and  Marion  counties.  A  very  severe  freeze,  however,  occurred 
April  23  and  24,  which  killed  all  the  apples  in  all  the  orchards  under 
consideration  except  the  one  located  at  Neoga,  in  Cumberland  county. 
As  a  result  the  experimental  work  was  abandoned  for  the  season  at  all 
points  except  the  orchard  at  Neoga,  and  one  at  Centralia  in  Marion 
county,  which  was  maintained  in  order  to  study  the  effects  of  the  vari- 
ous sprays  on  the  foliage. 

The  experimental  plats  at  Centralia  were  located  in  the  orchard  of 
G.  H.  Perrine  and  Sons.  The  trees  used  were  of  the  Ben  Davis  vari- 
ety, twenty-five  years  old. 

TREATMENT 

The  trees  were  sprayed  as  follows : 


Plat 

Appli- 
cation 

Date 

Time 

Treatment 

1 

1 

March   31 

Just  before  bloom 

Commercial    lime    sulfur 

2 

April     11 

Just  after  fall  of  petals 

diluted  1  to  30  with  ar- 

3 

April     20 

senate  of  lead,  4-100 

4 

May       31 

2 

1 

March   31 

Just  before  bloom 

Bordeaux,-  8-8-100,  with 

2 

April      13 

Just  after  fall  of  petals 

arsenate  of  lead,  4-100, 

3 

April     20 

followed        immediately 

4 

April     25 

A  maintenance  coat  of  milk  of 

with  milk  of  lime,  8-100, 

lime 

this  subsequent  coat  be- 

5 

May       16 

A  maintenance  coat  of  milk  of 

ing  maintained 

lime 

6 

May       31 

Just  before  bloom 

1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


127 


Plat 

Appli- 
cation 

Date 

Time 

Treatment 

3 

1 

March 

31 

Just  before  bloom                ,  Bordeaux,   8-8-100,  with 

2 

April 

13 

Just  after  fall  of  petals            arsenate  of  lead,  4-100 

3 

April 

20 

4 

May 

31 

4a 

1 

March 

31 

Just  before  bloom 

Homemade    lime    sulfur,1 

2 

April 

12 

Just  after  fall  of  petals 

without  sludge,  with  ar- 

3 

April 

20 

senate  of  lead,  4-100 

4 

June 

1 

4b 

1 

April 

1 

Just  before  bloom 

Homemade   lime    sulfur,1 

2 

April 

13 

Just  after  fall  of  petals 

with  sludge  added,  with 

3 

April 

20 

arsenate  of  lead,  4-100 

4 

June 

1 

5 

1 

April 

2 

Just  before  bloom 

Self  -boiled    lime     sulfur, 

2 

April 

14 

Just  after  fall  of  petals 

32-32-200,    with    arsen- 

3 

April 

22 

ate  of  lead,  4-100 

4 

May 

30 

6 

1 

April 

2 

Just  before  bloom 

Self-boiled    lime    sulfur, 

2 

April 

14 

Just  after  fall  of  petals 

16-16-100,  with  arsenate 

3 

April 

22 

of  lead,  4-100 

4 

May 

30 

7 

1 

April 

2 

Just  before  bloom 

Self-boiled    lime    sulfur, 

2 

April 

14 

Just  after  fall  of  petals 

10-10-50,  with  arsenate 

3 

April 

27 

of  lead,  4-100 

4 

May 

30 

8 

1 

April 

2 

Just  before  bloom 

Self-boiled    lime     sulfur, 

2 

April 

14 

Just  after  fall  of  petals 

8-8-50,  with  arsenate  of 

3 

April 

27 

lead,  4-100 

4 

May 

30 

9 

1 

April 

2 

Just  before  bloom 

Self-boiled    lime    sulfur, 

2 

April 

14 

Just  after  fall  of  petals 

6-6-100,    with    arsenate 

3 

April 

27 

of  lead,  4-50 

4 

May 

30 

11 

1 

April 

2 

Just  before  bloom 

Commercial    lime    sulfur 

2 

April 

13 

Just  after  fall  of  petals 

diluted  1  to  30  with  ar- 

3 

April 

28 

senate  of  lead    (acid),1 

4 

June 

1 

4-100 

12 

1 

April 

1 

Just  before  bloom 

Commercial    lime    sulfur 

2 

April 

13 

Just  after  fall  of  petals 

diluted  1  to  30  with  ar- 

? 

April 

28 

senate     of     lead     (nor- 

4 

June 

1 

mal),8  4-100 

13 

1 

April 

1 

Just  before  bloom 

Commercial    lime    sulfur 

2 

April 

13 

Just  after  fall  of  petals 

diluted  1  to  30  without 

3 

April 

28 

arsenate  of  lead 

4 

June 

1 

1Prepared  according  to  the  formula  recommended  by  J.  P.  Stewart,  Penn. 
State  Col.  Agr.  Exp.  Sta.  Bui.  92;  100  pounds  sulfur,  50  pounds  lime,  50  gallons 
water. 

2Hemingway  arsenate  of  lead. 
'Sherwin-Williams  arsenate  of  lead. 


128  BULLETIN  No.  185  [February, 

EFFECTS  OF  BORDEAUX  AND  LIME  SULFUR 

In  Plat  1,  commercial  lime  sulfur  controlled  apple  scab  well.  No 
spray  injury  was  observed  until  several  weeks  after  the  fourth  appli- 
cation, when  a  very  small  amount  became  noticeable.  The  leaves  on 
the  trees  in  this  plat  were  perceptibly  smaller  than  those  from  trees 
treated  with  a  spray  containing  a  surplus  quantity  of  lime,  as  were 
the  leaves  from  trees  sprayed  with  homemade  lime  sulfur  (Plat  4), 
but  they  had  excellent  color,  and  the  fruit  buds  formed  during  the 
season  were  very  large  and  numerous. 

Standard  Bordeaux  (8-8-100)  applied  to  the  trees  in  Plat  3  pro- 
duced severe  spray  injury,  but  not  until  after  the  third  application, 
when  many  leaves  turned  yellow  and  fell  to  the  ground.  The  fruit 
buds  on  this  plat  were  perceptibly  smaller  than  those  on  Plats  1,  4, 
and  5,  probably  because  of  the  severity  of  the  injury  to  the  foliage. 
Scab  was  controlled  by  the  standard  Bordeaux  both  in  this  plat  and  in 
Plat  2. 

EFFECTS  OF  HOMEMADE,  COMMERCIAL,  AND  SELF-BOILED  LIME  SULFUR 

The  homemade  mixture  of  lime  sulfur  did  not  control  the  scab  so 
well  as  the  commercial,  used  on  Plat  1.  Altho  the  damage  was  small, 
homemade  lime  sulfur  resulted  in  more  foliage  injury  than  commercial 
lime  sulfur,  and  this  injury  came  earlier  in  the  season.  The  foliage, 
however,  was  very  good,  and  the  fruit  buds  were  apparently  as  large 
and  as  numerous  as  in  Plat  1. 

Plat  5,  where  the  trees  were  sprayed  with  self -boiled  lime  sulfur, 
showed  very  little  benefit  from  the  spray.  Scab  was  present  in  almost 
as  large  quantities  as  on  the  untreated  foliage  of  the  check  trees.  The 
leaves  on  the  trees  sprayed  with  self-boiled  lime  sulfur  appared  to  be 
larger  than  those  on  the  other  trees  sprayed  with  lime  sulfur.  This 
spray  made  the  tree  and  foliage  very  white,  and  the  material  stuck 
well.  Its  fungicidal  value,  however,  proved  small. 

EFFECTS  OF  ADDING  LIME-SULFUR  SLUDGE  TO  A  CLEAR  SOLUTION  OF 

LIME  SULFUR 

In  Plat  4  one-half  the  trees  were  sprayed  with  homemade  lime  sul- 
fur with  the  sludge  included,  and  the  other  half  without  the  sludge. 
The  lime  sulfur  was  made  by  G.  H.  Perrine  and  Sons  at  the  beginning 
of  the  season  and  kept  as  a  stock  solution.  The  specific  gravity  of  the 
material  was  determined  by  hydrometer  test  and  the  spray  used  at  a 
dilution  corresponding  to  the  strength  of  the  commercial  material. 
The  trees  which  were  sprayed  with  the  homemade  mixture  combined 
with  the  sludge,  Plat  4b,  were  more  plainly  marked  by  the  spray,  but 
no  difference  in  the  vigor  or  color  of  the  foliage  could  be  detected, 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  129 

either  favorable  or  unfavorable,  as  a  result  of  the  presence  of  the 
sludge  in  the  mixture. 

EFFECTS  OF  SELF-BOILED  LIME  SULFUR  MADE  IN  VARYING  PROPORTIONS 

All  combinations  gave  very  similar  results  as  far  as  could  be  de- 
termined from  the  foliage.  The  amounts  of  scab  and  insect  injury  on 
the  foliage  in  each  of  the  plats  were  very  similar,  as  were  also  the  vigor 
and  color  of  the  leaves.  Compared  with  untreated  trees  and  with  trees 
sprayed  with  Bordeaux  and  ordinary  lime  sulfur,  these  plats  demon- 
strated the  inefficiency  of  self -boiled  lime  sulfur  as  a  fungicide  for 
apple  foliage. 

EFFECTS  OF  ACID,  NEUTRAL,  AND  MIXED  ARSENATES  OF  LEAD 

As  the  principal  purpose  of  arsenate  of  lead  is  the  control  of  in- 
sects affecting  the  fruit,  the  results  of  these  tests  in  1910  are  of  com- 
paratively little  value.  All  brands  of  arsenate  of  lead  gave  equally 
good  control  of  insects  affecting  the  foliage.  Arsenate  of  lead  com- 
bined with  lime  sulfur  increased  the  fungicidal  value  of  the  mixture 
over  lime  sulfur  alone,  as  indicated  by  the  control  of  scab.  Slight 
spray  injury  occurred  in  all  the  plats  in  this  group  but  no  differences 
in  amounts  or  character  could  be  observed. 


130 


BULLETIN  No.  185 


[February, 


SPRAYING  EXPERIMENTS  IN  1911  AT  CENTRALIA, 
MARION  COUNTY 

BY  L.  EARL  FOGLESONG 


OBJECTS 

The  objects  of  the  experiments  at  the  Centralia  orchard  in  1911 
were:  (1)  to  test  the  efficiency  of  Bordeaux  and  lime  sulfur  as  fungi- 
cides for  the  apple;  (2)  to  determine  whether  or  not  applications  of 
lime  sulfur  made  while  the  trees  are  dormant  have  any  value  in  con- 
trolling scab  and  other  diseases  during  the  succeeding  growing  season ; 
(3)  to  compare  the  efficiency  of  light  and  heavy  applications  of  Bor- 
deaux and  lime  sulfur ;  (4)  to  learn  the  effects  of  adding  copper  sul- 
f ate  to  lime  sulfur  in  order  to  increase  the  f ungicidal  value  of  the  mix- 
ture ;  and  (5)  to  determine  the  effects  of  maintaining  a  Bordeaux  coat- 
ing on  the  fruit  and  foliage  by  sealing  it  in  with  a  second  coating  of 
Bordeaux  or  with  a  coating  of  milk  of  lime,  the  coating  to  be  renewed 
with  sufficient  frequency  during  the  season  to  protect  the  first  applica- 
tion from  the  action  of  rain  and  air. 

LOCATION  AND  DESCRIPTION   OF  ORCHARD 

The  plats  under  treatment  were  located  in  the  same  orchard  and  in 
the  same  block  of  trees  as  those  of  the  experiments  in  1910. 

OUTLINE  OF  TREATMENTS 

Sixteen  plats  arranged  as  shown  in  Chart  7  were  sprayed  as  fol- 
lows: 


Plat 

Appli- 
cation 

Date 

Time 

Treatment 

A 

1 

April 

15 

Just  before  bloom 

Bordeaux  arsenate  of  lead 

2 

May 

2 

Just  after  fall  of  petals 

Lime  sulfur  arsenate  of  lead 

3 

May 

16 

Lime  sulfur  arsenate  of  lead 

4 

June 

26 

Lime  sulfur  arsenate  of  lead 

B 

1 

April 

15 

Just  before  bloom 

Bordeaux  arsenate  of  lead 

2 

May 

4 

Just  after  fall  of  petals 

Bordeaux  arsenate  of  lead 

3 

May 

16 

Lime  sulfur  arsenate  of  lead 

4 

June 

29 

Lime  sulfur  arsenate  of  lead 

G 

1 

April 

15 

Just  before  bloom 

Lime  sulfur  arsenate  of  lead 

2 

May 

4 

Just  after  fall  of  petals 

Bordeaux  arseuate  of  lead 

3 

May 

15 

Bordeaux  arsenate  of  lead 

4 

June 

27 

Bordeaux  Hrsenate  of  lead 

D 

1 

April 

15 

Just  before  bloom 

Lime  sulfur  arsenate  of  lead 

2      ;  May 

2  Just  after  fall  of  petals 

Lime  sulfur  arsenate  of  lead 

3      ,May 

15 

Bordeaux  arsenate  of  lead 

4       June 

27 

Bordeaux  arsenate  of  lead 

1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


131 


Plat 

Appli- 
cation 

Date 

Time 

Treatment 

E 

1 

April 

15  'Just  before  bloom 

Lime  sulfur  arsenate  of  lead 

2 

May 

2 

Just  after  fall  of  petals 

Lime  sulfur  arsenate  of  lead 

3 

May 

16 

Lime  sulfur  arsenate  of  lead 

4 

June 

29 

Lime  sulfur  arsenate  of  lead 

P 

1 

April 

15 

Just  before  bloom 

Lime  sulfur  arsenate  of  lead, 

2 

May 

3 

Just  after  fall  of  petals 

4  applications.  This  plat  re- 

3 

May 

16 

ceived    no    winter    applica- 

4 

June 

29 

tion  of  lime  sulfur 

G 

1 

April 

15 

Just  before  bloom 

Bordeaux  arsenate  of  lead,  4 

2 

May 

4 

Just  after  fall  of  petals 

applications.  This  plat  had 

3 

May 

15 

received  no  winter  applica1 

4 

June 

26 

tion  of  lime  sulfur 

H 

1 

April 

15 

Just  before  bloom 

Bordeaux  arsenate  of  lead,  4 

2 

May 

4 

Just  after  fall  of  petals 

applications.  This  material 

3 

May 

15 

was  applied  in  large  quan- 

4 

June 

27 

tities 

I 

1 

April 

15 

Just  before  bloom 

Bordeaux  arsenate  of  lead,  4 

2 

May 

4 

Just  after  fall  of  petals 

applications.  This  material 

3 

May 

15 

was    applied   in    quantities 

4 

June 

29 

even  less  than  for  the  ordi- 

nary spraying 

J 

1 

April 

15  Just  before  bloom 

Bordeaux  arsenate  of  lead,  4 

2 

May 

4  Just  after  fall  of  petals 

regular  applications.  Extra 

3 

May 

15 

applications  were  for  main- 

4 

June 

6 

An  extra  application 

taining  the  coating  of  Bor- 

5 

June 

28 

deaux  and  were  made  of  tho 

6 

July 

21 

An  extra  application 

same  material 

7 

Aug. 

12 

An  extra  application 

K 

1 

April 

15 

Just  before  bloom 

Bordeaux  arsenate  of  lead,  4 

2 

May 

4 

Just  after  fall  of  petals 

regular  applications.  Extra 

3 

May 

15 

applications  were  for  main- 

4 

June 

6 

An  extra  application 

taining  the  coating  of  Bor- 

5 

June 

29 

deaux  and  were  made  with 

6 

July 

21 

An  extra  application 

milk  of  lime,  8-100 

7 

Aug. 

12 

An  extra  application 

L          1 

April 

15 

Just  before  bloom 

Bordeaux  alone,  8-8-100 

2 

May 

2 

Just  after  fall  of  petals 

Arsenate  of  lead,  4-100 

3 

May 

16 

Arsenate  of  lead,  4-100 

4 

June 

28 

Arsenate  of  lead,  4-100 

M          1 

April 

15 

Just  before  bloom 

Lime  sulfur  alone,  1—17 

2 

May 

2 

Just  after  fall  of  petals 

Arsenate  of  lead,  4-100 

3 

May 

16 

Arsenate  of  lead,  4-100 

4 

June 

28 

Arsenate  of  lead,  4-100 

N 

1 

April 

15 

Just  before  bloom 

Lime  sulfur,  1-17,  with  cop 

2 

May 

2 

Just  after  fall  of  petals 

per  sulfate,  4-100 

3 

May 

16 

4 

June 

29 

132 


BULLETIN  No.  185 


[February, 


Plat 

Appli- 
cation 

Date 

Time 

Treatment 

O 

1 

'April 

15 

Just  before  bloom 

Lime  sulfur,  1-17,  with  cop- 

2 

May 

2 

Just  after  fall  of  petals 

per  sulfate,  8-100 

3 

May 

16 

4 

June 

29 

P 

1 

April 

15 

Just  before  bloom 

Lime  sulfur,  1-17,  with  cop- 

2 

May 

2 

Just  after  fall  of  petals 

per  sulfate,  12-100 

3 

May 

16 

4 

June 

29 

O 


O 


O  O 


O 


o 


O 


o 


oo 


Winesap 


(Q)B*n  DavU.  (&)  Ben  Daris   Check        QRestt. 

CHART  7.  —  PLAN  OF  PLATS  IN  ORCHARD  OF  G.  H.  PERRINE  AND  SONS,  CENTRALIA, 

1911 


APPARATUS  AND   PREPARATION   OF   MATERIALS 

A  gasoline  power  spray  outfit  equipped  with  spray  tower  belonging 
to  G.  H.  Perrine  and  Sons  was  used  to  make  all  the  applications.  The 
spray  was  applied  at  a  pressure  of  approximately  150  pounds  to  the 
square  inch.  The  lime  sulfur  used  thruout  these  experiments  was 
made  by  G.  H.  Perrine  and  Sons  in  a  newly  installed  steam  cooker. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  133 

It  was  made  according  to  the  Illinois  formula:  50  pounds  lime,  100 
pounds  sulfur,  and  66  gallons  water.  While  the  trees  were  dormant, 
the  spray  was  applied  at  a  dilution  of  1  gallon  of  lime  sulfur  to  7  gal- 
lons of  water.  During  the  summer  it  was  applied  at  a  dilution  of  1 
gallon  to  17  of  water.  Bordeaux  was  made  on  the  standard  formula : 
8  pounds  lime,  8  pounds  copper  sulfate,  and  100  gallons  water.  Arsen- 
ate  of  lead  at  the  rate  of  4  pounds  to  each  100  gallons  of  spray  mix- 
ture was  used  at  all  applications  unless  otherwise  noted. 

CHARACTER  OF  RECORDS  AND  METHOD  OP  MAKING 

A  record  of  daily  temperatures,  rainfall,  cloudiness,  and  wind  was 
made.  Notes  were  taken  from  time  to  time  on  the  amount,  vigor,  and 
color  of  the  foliage.  All  dropped  apples  were  examined  to  determine 
the  effects  of  the  sprays  in  preventing  injury  from  insects  and  fungi. 
At  the  close  of  the  season  the  apples  were  picked,  and  four  representa- 
tive trees  were  selected  from  each  plat  and  from  each  check  row  for 
record  making.  Fifty  apples  chosen  at  random  from  the  crop  of  each 
tree  were  taken  from  the  sorting  table  and  examined  for  evidences  of 
scab,  sooty  blotch,  flyspeck,  bitter  rot,  blotch,  and  other  fungous  dis- 
eases, and  for  injuries  from  codling  moth,  curculio,  and  other  insects. 
The  data  obtained  thruout  the  season  were  later  tabulated  for  detailed 
study. 

WEATHER  CONDITIONS 

The  weather,  tho  significant  in  this  year 's  data,  did  not  cause  much 
trouble  at  or  during  the  spraying  periods.  The  times  of  spraying 
Plats  J  and  K  were  dependent  on  the  occurrence  of  rains. 

A  cold  rain  which  continued  from  April  27  to  April  29  fell  during 
the  blossoming  period  and  prevented  the  pollination  of  the  large  set  of 
blossoms.  The  crop  was,  therefore,  light,  and  because  of  this  fact  the 
records  obtained  from  the  fruit  were  less  conclusive  than  was  desired. 

EFFECT  ON  FOLIAGE 

In  the  general  study  of  the  foliage,  spray  injury  was  particularly 
noted.  More  or  less  injury  was  caused  by  all  the  sprays,  altho  the 
time  of  application  was  an  important  factor  in  this  connection. 

The  lime  sulfur  used  at  the  third  application  was  unusually  harm- 
ful this  year, — more  so  than  in  any  year  since  the  writer  has  closely 
observed  its  action.  Oversprayed  branches  were  the  most  severely 
burned.  The  injury  to  the  foliage,  however,  was  soon  effaced  as  far 
as  the  eye  could  discern.  Badly  burned  leaves  fell  and  the  remaining 
Leaves  were  rich  in  color  and  apparent  vigor. 

Bordeaux  injured  the  foliage  and  russeted  the  fruit.  The  apples 
russeted  by  the  lime-sulfur  spray  looked,  and  really  were  much  less  in- 
jured in  the  fall  than  in  midsummer,  the  injury  thinning  out  and  be- 
coming inconspicuous ;  but  the  Bordeaux-sprayed  apples  were  in  many 


134  BULLETIN  No.  185  [February, 

instances  so  severely  injured  as  to  be  unmarketable.  More  foliage  was 
lost  from  the  Bordeaux-sprayed  trees  than  from  those  sprayed  with 
lime  sulfur,  and  the  general  appearance  thruout  the  summer  was 
poorer. 

The  foliage  of  Plats  J  and  K  (sprayed  with  Bordeaux)  was  much 
poorer  than  that  of  the  plats  sprayed  a  fewer  number  of  times  with 
the  same  mixture.  The  repetition  of  the  spray  was  detrimental  under 
the  conditions  of  this  year.  In  percentage  of  injury  and  general  ap- 
pearance, these  two  plats  varied  but  little. 

The  foliage  on  Plats  L  and  M  (sprayed  with  Bordeaux  arsenate 
of  lead,  and  lime  sulfur  arsenate  of  lead,  respectively)  was  good 
average  foliage  at  the  close  of  the  season.  The  amount  of  injury 
present  was  much  less  than  that  produced  by  Bordeaux  alone,  and 
slightly  less  than  that  produced  by  lime  sulfur  alone.  There  were  sev- 
eral severe  attacks  of  yellow-leaf  on  these  plats  when  no  other  plat 
was  so  infested. 

The  appearance  of  the  foliage  in  Plats  N,  0,  and  P  was  generally 
below  the  average  of  the  other  plats.  The  sprays  resulted  in  consid- 
erable foliage  and  fruit  injury  and  there  was  a  dark  discoloration  on 
the  bark,  foliage,  and  fruit,  due  to  the  copper  and  sulfur  compound, 
that  was  unsightly  to  one  accustomed  to  the  light  appearance  caused 
by  other  sprays. 

A  good  deal  of  injury  was  caused  this  year  by  all  sprays,  which  in 
order  of  severity  ranked  as  lollows :  Bordeaux,  copper  sulf  ate  and  lime 
sulfur,  lime  sulfur,  and  arsenate  of  lead. 

EFFECT  ON  FRUIT 

The  fruit  from  these  plats  was  picked  and  examined  in  October, 
with  the  results  presented  in  Tables  28  and  29. 

Scab. — Bordeaux,  lime  sulfur,  and  the  combination  of  lime  sulfur 
and  copper  sulfate  all  reduced  the  amount  of  scab  to  a  very  marked 
degree  as  compared  with  the  check  plats.  Even  Plat  M,  which  showed 
the  poorest  control  of  any  sprayed  plat,  gave  only  12  percent  of  scabby 
apples,  as  compared  with  44  percent  for  the  unsprayed  trees.  Plats 
A,  B,  Gr,  H,  J,  K,  and  L,  all  of  which  received  Bordeaux  for  the  first 
application,  showed  an  average  of  only  3  percent  of  scabby  apples, 
whereas  those  plats  receiving  lime  sulfur  at  the  first  application  aver- 
aged 5.5  percent.  The  difference,  tho  small,  rather  consistently  fa- 
vored Bordeaux  for  the  first  spray.  In  the  present  season,  the  spray 
applied  before  the  blossoms  opened  was  clearly  the  important  one  in 
the  control  of  scab.  Where  no  fungicide  was  used  after  the  blossoms 
fell,  as  in  Plats  L  and  M,  the  control  of  this  disease  was  good.  The  re- 
sults for  these  two  plats  favored  Bordeaux  as  a  first  application  more 
strongly  than  the  general  results  for  the  whole  series  of  treatments; 
Plat  L,  which  received  Bordeaux,  showed  only  7  percent  of  scab,  as 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


135 


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BULLETIN  No.  185 


[February, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  137 

contrasted  with  Plat  M,  which  received  lime  sulfur  and  showed  1 2  per- 
cent of  scab.  It  will  be  observed  that  the  treatment  in  both  plats 
left  sufficient  infection  to  cause  serious  damage  in  a  season  favor- 
able for  the  development  of  scab.  There  is  no  evidence  to  show  that 
the  dormant-tree  application  exerted  any  influence  in  checking  it. 

Blotch. — Bordeaux,  when  used  for  the  second  and  third  spray- 
ings, gave  better  results  in  the  control  of  blotch  than  lime  sul- 
fur, as  may  be  seen  by  comparing  Plats  C,  Gr,  H,  J,  and  K,  all  of 
which  received  Bordeaux  for  the  second  and  third  applications, 
with  Plats  A  and  F,  which  received  lime  sulfur  for  the  same  two  ap- 
plications. Plat  E,  sprayed  with  lime  sulfur  thruout  the  season, 
showed  only  6  percent  of  blotch,  a  control  almost  as  good  as  the  aver- 
age plat  where  Bordeaux  was  used  in  one  or  more  of  the  final  spray- 
ings, but  not  so  good  as  where  Bordeaux  was  used  exclusively,  as  in 
Plats  H,  J,  and  L.  Arsenate  of  lead  alone  was  quite  ineffective  as  a 
fungicide  for  blotch,  Plats  L  and  M,  which  received  only  arsenate  of 
lead  at  the  two  final  sprayings,  showing  more  blotch  than  even  the 
untreated  plats.  Lime  sulfur  with  copper  sulfate  reduced  blotch  no- 
ticeably, but  was  no  more  effective  than  lime  sulfur  alone,  and  was 
considerably  less  effective  than  Bordeaux. 

Sooty  Blotch. — Sooty  blotch  was  better  controlled  by  Bordeaux, 
when  used  for  the  third  or  fourth  application,  than  by  lime  sulfur. 
The  addition  of  the  larger  quantities  of  copper  sulfate  to  lime  also 
resulted  in  a  marked  reduction  in  the  amount  of  sooty  blotch.  Arsen- 
ate of  lead,  however,  proved  ineffective  as  a  fungicide  for  this  disease. 

Decay. — Black  rot  was  common  on  all  the  check  plats.  Except  in 
the  plats  sprayed  with  arsenate  of  lead  at  the  second  and  third  appli- 
cations, and  in  Plat  N,  where  two  pounds  of  copper  sulfate  were  added 
to  the  regular  dilution  of  lime  sulfur,  there  was  a  lessening  of  the  dis- 
ease as  a  result  of  all  the  sprays.  In  this  respect  Bordeaux  and  lime 
sulfur  proved  about  equally  effective. 

Codling  Moth. — The  infestation  of  codling  moth  in  the  various 
plats  could  hardly  have  been  uniform,  since  Plats  B  and  D,  which  were 
properly  sprayed  with  arsenate  of  lead  in  combination  with  Bordeaux 
or  lime  sulfur,  showed  considerably  more  infection  than  the  composite 
check  plat,  while  Plats  A  and  C,  which  were  similarly  sprayed,  showed 
nearly  as  much.  The  infestation  in  the  several  check  plats  was  also 
very  uneven.  Comparing  treated  plats  with  their  adjoining  checks,  a 
fair  degree  of  control  is  found.  Comparing  the  average  injury  from 
codling  moth  on  all  sprayed  plats,  except  B  and  D,  with  the  composite 
check,  it  is  found  that  the  sprayed  plats  showed  an  average  percentage 
of  4.2  injured  apples  and  the  check  plats  an  average  percentage  of  12. 

Curculio. — The  results  indicated  a  somewhat  uneven  distribution 
of  infestation  by  the  curculio.  On  the  average,  the  sprayed  plats 
showed  less  injury  than  the  checks,  and  Plats  A,  C,  J,  K,  and  P  showed 


138  BULLETIN  No.  185  [February, 

decidedly  fewer  injured  apples  than  the  unsprayed  plats.  On  the 
other  hand  the  other  sprayed  plats  showed  so  little  difference  from 
the  checks  that  definite  conclusions  cannot  be  based  on  the  results. 

Russet. — Bordeaux  and  the  combination  of  lime  sulfur  and  copper 
sulf ate  were  responsible  for  more  russeting  of  the  fruit  than  lime  sul- 
fur or  arsenate  of  lead.  Where  Bordeaux  or  the  combination  of  lime 
sulfur  and  copper  sulf  ate  were  used  for  all  applications  (Plats  G,  H, 
J,  K,  N,  0,  and  P),  more  than  85  percent  of  all  the  apples  were  more 
or  less  russeted.  Plats  E  and  F,  sprayed  thruout  the  season  with  lime 
sulfur,  showed  only  66  percent  of  russeted  apples,  and  the  russet  on 
this  fruit  was  trivial  in  character  compared  with  that  on  the  apples  of 
the  other  plats,  only  iy2  percent  being  severely  russeted. 

Burn. — This  is  an  arbitrary  term  which  was  immediately  and  sug- 
gestively applied  to  an  injury  found  on  the  trees  sprayed  with  lime 
sulfur  this  summer.  It  was  found  most  often  on  the  south  and  west 
sides  of  the  trees,  and  might  have  been  called  a  sun  scald  but  for  the 
fact  that  it  was  found  only  on  lime-sulfur  sprayed  trees.  The  burn 
followed  both  the  third  and  fourth  applications. 

SUMMARY  OF  RESULTS  AT  CENTRALIA,  1911 

1.  The  season's  work  confirms  the  already  well-established  effec- 
tiveness of  Bordeaux  as  a  fungicide  for  the  control  of  scab,  blotch, 
sooty  blotch,  and  black  rot.     It  indicates  also  that  lime  sulfur  pos- 
sesses only  slightly  less  efficient  fungicidal  properties,  at  least  in  a  dry 
season,  than  Bordeaux.    Both  fungicides  caused  some  injury  to  the 
fruit,  Bordeaux  in  the  form  of  russet  and  lime  sulfur  in  the  form  of 
burn.    Bordeaux  was  more  injurious  to  the  foliage,  causing  some  yel- 
low-leaf and  much  spotting.    On  the  whole,  honors  for  the  two  sprays 
were  even. 

2.  Applications  of  lime  sulfur  made  while  the  trees  were  dormant 
failed  to  exercise  any  controlling  effect  over  apple  scab  or  blotch  dur- 
ing the  ensuing  season. 

3.  No  results  were  obtained  bearing  on  the  comparative  effects  of 
heavy  and  light  applications  of  Bordeaux  and  lime  sulfur. 

4.  The  addition  of  copper  sulfate  to  lime  sulfur  proved  unnec- 
essary and  inadvisable,  owing  to  the  severe  injury  which  it  caused  to 
foliage  and  fruit. 

5.  Double  applications  of  Bordeaux  and  coatings  of  milk  of  lime 
were  not  more  satisfactory  than  single  applications  of  Bordeaux  in  the 
control  of  scab.    Double  applications  of  Bordeaux  were  more  injurious 
to  the  foliage  and  caused  more  russeting  of  the  fruit  than  single  ap- 
plications. 

6.  Arsenate  of  lead  alone  showed  no  noticeable  fungicidal  prop- 
erties. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  139 


SPRAYING  EXPERIMENTS  IN  1912  AT  ANNA, 
UNION  COUNTY 

BY  L.  EAEL  FOGLESONG 
OBJECTS 

In  formulating  this  year's  spray  schedule  the  following  questions 
were  considered  and  groups  of  treatments  were  arranged  with  a  view 
toward  their  solution:  (1)  the  relative  efficiency  of  Bordeaux  and  lime 
sulfur;  (2)  the  relative  efficiencies  of  various  dilutions  of  lime  sulfur; 
(3) the  relative  efficiencies  of  moderate  and  heavy  applications  of 
Bordeaux;  (4)  the  relative  efficiencies  of  various  classes  of  arsenate  of 
lead ;  (5)  the  fungicidal  value  of  various  arsenates  of  lead  when  added 
to  lime  sulfur;  (6)  the  possibility  of  interchanging  lime  sulfur  for 
Bordeaux,  or  vice  versa;  (7)  the  best  time  and  number  of  times  for 
spray  applications;  and  (8)  the  value  of  copper  ferrocyanide,  both 
as  a  fungicide  and  as  an  insecticide. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

The  orchard  used  for  these  experiments  is  located  in  Union  county, 
three  miles  southwest  of  Anna,  in  the  unglaciated  portion  of  southern 
Illinois.  This  orchard,  which  is  owned  by  Mr.  F.  P.  Anderson,  of 
Anna,  has  been  well  sprayed,  pruned,  and  cultivated.  There  are  a 
large  number  of  varieties  of  apples  on  the  farm,  but  the  experiments 
were  made  only  on  Jonathan  and  Winesap.  With  but  few  exceptions 
the  treatment  was  the  same  for  each  variety. 

TREATMENT 

The  experimental  areas  were  divided  into  plats,  each  of  which  was 
treated  in  the  manner  described  in  the  various  tables  which  are  pre- 
sented in  connection  with  the  results  which  were  obtained.  The 
arrangement  of  these  plats  is  shown  in  Charts  8  and  9. 

APPARATUS  AND  PREPARATION  OP  MATERIALS 

Unless  otherwise  stated,  the  Bordeaux  used  in  these  treatments 
was  made  on  the  formula,  8  pounds  copper  sulfate,  8  pounds  lime, 
and  100  gallons  water.  The  lime  sulfur  was  a  commercial  brand 
testing  between  32.5°  and  33°  Baume,  or  1.2889  and  1.2946  specific 
gravity,  and  was  used  at  the  rate  of  3  gallons  in  100  gallons  of  the 
diluted  mixture  (approximately  8  pounds  sulfur  in  100  gallons)  ; 
arsenate  of  lead  in  the  paste  form  was  added  to  the  diluted  spray  mix- 
ture at  the  rate  of  4  pounds  per  100  gallons.  The  copper  ferrocyanide 


140 


BULLETIN  No.  185 


[February, 


Oo 


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Jonathans    Resets 


.  Davis 


CHART  8.  —  PLAN  OF  PLATS  IN  JONATHAN  BLOCK  IN  ORCHARD  OF 
MR.  F.  P.  ANDERSON,  ANNA,  1912 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


141 


QOO 


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Wlaesap  Resets   Y.  Transparent 


CHART  9.  —  PLAN  OF  PLATS  IN  WINESAP  BLOCK  IN  ORCHARD  OF 
MR.  F.  P.  ANDERSON,  ANNA,  1912 


142  BULLETIN  No.  185  [February, 

was  made  on  the  formula,  2  pounds  potassium  ferroeyanide,  2  pounds 
copper  sulfate,  and  100  gallons  water.  The  two  substances  were  mixed 
at  equal  and  full  dilutions.  Each  plat  was  sprayed  three  times  after 
the  dormant-tree  spray;  Application  1  was  made  when  the  blossoms 
were  in  the  cluster-bud  stage;  Application  2  was  made  immediately 
after  the  fall  of  the  petals ;  and  Application  3  was  made  about  10  days 
after  Application  2.  The  Jonathan  block  was  sprayed  with  winter- 
strength  lime  sulfur  (1  to  10)  April  6;  the  Winesap  block  received  a 
similar  spraying,  April  10,  at  a  strength  of  1  to  12,  the  weaker  dilution 
being  used  because  the  buds  were  farther  advanced  at  that  time.  Two 
additional  summer  applications  were  made  to  certain  plats  in  the 
Winesap  block.  All  applications  were  made  with  a  gasoline  power 
outfit  equipped  with  a  tower,  to  permit  spraying  the  entire  tree.  The 
spray  was  applied  at  a  pressure  of  200  pounds  per  square  inch,  using 
Vermorel  nozzles  for  the  first  application,  Bordeaux  nozzles  for  the 
second  application,  and  Friend  nozzles  for  all  succeeding  applications. 

CHARACTER  OF  RECORDS  AND   METHOD  OP  MAKING 

Foliage. — Notes  were  made  during  the  early  part  cf  the  season  at 
weekly  intervals,  and  during  the  latter  part  of  the  season  at  bi-weekly 
intervals,  on  the  vigor,  color,  and  amount  of  foliage.  Comparisons 
were  thus  obtained  of  the  effectiveness  of  the  various  spray  mixtures 
used  in  controlling  the  insect  pests  and  fungous  diseases  which  attack 
the  foliage  of  the  apple.  Direct  effects  of  the  spray  mixtures  them- 
selves upon  the  foliage  were  also  observed.  They  were  in  the  form  of 
injuries  to  the  leaves,  and  included  a  brown  spotting  and  the  yellow- 
ing of  part  of  the  foliage  as  a  result  of  certain  applications.  Altho 
these  effects  alone  were  not  sufficient  to  base  conclusions  upon,  they 
were,  nevertheless,  important  in  the  compilation  and  study  of  results 
from  the  spraying  treatments. 

Fruit. — Two  hundred  of  the  dropped  apples  from  each  tree  were 
examined  to  secure  records  of  their  injuries.  Where  the  number  of 
"dropped  apples"  was  less  than  200,  all  the  fallen  fruit  was  exam- 
ined. The  records  on  the  picked  fruit  were  made  in  the  following 
manner:  The  apples  from  all  of  the  trees  except  those  discarded  be- 
cause of  deviation  from  the  standard  type  within  the  block,  diseased 
and  undersized  trees,  trees  which  failed  to  bloom,  trees  of  odd  vari- 
eties, or  trees  which  for  other  reasons  were  not  typical  of  those  within 
the  plat,  were  counted,  graded,  and  weighed.  The  samples  examined, 
which  included  200  apples  each,  were  collected  at  random  from  the 
whole  crop  produced  by  each  tree,  in  the  same  manner  and  under  the 
direction  of  the  same  man,  in  an  attempt  to  secure  a  uniform  com- 
parison thruout  the  plats.  A  workman  chosen  for  his  reliability  and 
good  sense  picked  from  each  tree  the  required  number  of  apples.  His 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  143 

ladder  was  placed  at  least  four  times  for  each  tree,  once  in  each  quar- 
ter of  the  tree.  The  apples  were  picked  without  regard  to  size,  blem- 
ishes, or  other  quality,  in  order  to  secure  samples  that  fairly  repre- 
sented the  crop. 

WEATHER  CONDITIONS 

The  weather  at  the  time  of  the  dormant  spraying  was  cloudy,  and 
a  very  light  rain  followed  the  application  made  to  the  Jonathan  block. 
At  the  time  of  the  first  summer  spraying  (the  cluster-bud  spraying) 
the  weather  was  windy  and  cloudy  with  more  or  less  rain.  Plats  1 
and  2  had  to  be  resprayed,  as  it  was  believed  that  more  or  less  spray 
material  was  washed  off  by  rains  which  occurred  soon  after  its  appli- 
cation. At  the  time  of  the  second  application  the  weather  was  again 
cloudy,  but  no  rainfall  occurred  to  prevent  the  completion  of  the  reg- 
ularly scheduled  work.  Ideal  weather  prevailed  at  the  time  of  the 
third  application ;  there  was  a  bright  sun,  very  little  wind,  and  no 
rainfall.  Rain  interfered  with  both  the  later  summer  applications ;  it 
was  necessary,  however,  to  make  them  as  nearly  at  the  correct  time  as 
could  be  done  under  the  circumstances,  respraying  the  plats  where  the 
spray  appeared  to  be  washed  off  by  rains  which  followed  the  oper- 
ation. The  latter  part  of  the  summer  was  dry. 

EFFECT  ON  FOLIAGE  FOR  ALL  TREATMENTS 

The  observations  on  the  effects  of  the  different  sprays  on  the  foliage 
are  summarized  as  follows:  Where  lime  sulfur  alone,  lime  sulfur 
arsenate  of  lead,  copper  ferrocyanide  alone,  and  copper  ferrocyanide 
arsenate  of  lead  were  used  for  the  first  application,  no  spray  injury 
resulted.  Bordeaux  arsenate  of  lead,  at  the  time  of  the  first  applica- 
tion, appeared  to  cause  a  small  amount  of  burning  of  the  foliage,  the 
injury  being  confined  to  the  tips  of  the  expanding  leaves.  In  the  case 
of  the  second  application,  some  injury  to  the  foliage  resulted  from 
the  application  of  lime  sulfur  alone,  and  also  from  lime  sulfur  ar- 
senate of  lead.  None  appeared  to  follow  the  application  of  Bordeaux 
arsenate  of  lead  or  copper  ferrocyanide  after  the  second  application. 

The  spray  was  applied  without  any  immediate  injury  to  the  foliage 
from  any  of  the  spraying  materials  used.  Two  weeks,  however,  after 
the  third  application,  the  trees  sprayed  with  Bordeaux  began  to  show 
noticeable  foliage  injury,  particularly  in  the  Jonathan  block.  Two 
severe  epidemics  of  yellow-leaf  occurred  on  the  trees  where  Bordeaux 
was  used.  Each  outbreak  followed  a  period  of  rainy  or  cloudy  weather 
in  the  Jonathan.  It  is  estimated  that  25  percent  of  all  the  Bordeaux- 
sprayed  foliage  in  the  Jonathan  block  turned  yellow  and  fell  to  the 
ground  in  the  course  of  these  two  epidemics.  The  attacks  of  yellow- 
leaf,  were,  however,  much  more  severe  in  the  Jonathan  block  than  in 
the  Winesap  block.  Injury  began  to  appear  on  the  leaves  of  the  trees 


144 


BULLETIN  No.  185 


[February, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  145 

sprayed  with  copper  ferrocyanide  alone,  and  also  on  those  sprayed 
with  copper  ferrocyanide  arsenate  of  lead,  at  the  same  time  that  the 
Bordeaux  injury  began  to  show  after  the  third  application,  that  is, 
about  two  weeks  after  the  time  of  spraying. 

EFFECTS  OF  BORDEAUX  AND  LIME  SULFUR 

Table  30  presents  the  data  recorded  on  the  Jonathan  plats  sprayed 
with  corresponding  applications  of  Bordeaux  and  lime  sulfur.  The 
effects  of  these  treatments  were  as  follows : 

Scab. — The  variety  Jonathan  is  not  very  subject  to  scab;  conse-1 
quently,  it  does  not  furnish  as  good  comparative  spray  data  as  may  be 
secured,  for  example,  from  Winesap,  Ben  Davis,  or  Mammoth  Black 
Twig.  From  the  data  in  Table  30,  we  may  conclude  that  the  two 
sprays  in  question  are  of  practically  equal  fungicidal  value.  The  re- 
sults slightly  favor  Bordeaux,  tho  the  difference  is  easily  within  the 
range  of  experimental  error. 

Sooty  Blotch. — Bordeaux  controlled  this  disease  more  effectively 
than  lime  sulfur,  possibly  on  account  of  its  superior  adhesiveness. 

Codling  Moth. — Lime  sulfur  arsenate  of  lead  gave  results  slightly 
superior  to  Bordeaux  arsenate  of  lead  in  the  control  of  the  first  brood 
of  codling  moth,  as  indicated  by  the  relative  numbers  of  picked  apples 
which  had  been  entered  by  the  insects.  Taking  the  dropped  apples 
into  account,  however,  the  differences  are  scarcely  consistent. 

Curculio. — Very  little  difference  in  the  comparative  control  of  cur- 
culio  was  shown  by  the  two  sprays.  Both  reduced  the  injury  from  this 
insect  on  picked  apples  by  amounts  varying  from  12  to  19  percent. 

Russet. — Lime  sulfur  caused  very  little  russet,  whereas  Bordeaux 
caused  a  large  amount,  some  of  which  was  very  serious  in  character. 

Table  31  presents  the  data  derived  from  the  comparative  tests  of 
Bordeaux  and  lime  sulfur  on  the  Winesap  plats.  It  also  shows  the  ef- 
fects of  the  various  applications  applied  singly  and  in  all  combina- 
tions. The  effects  of  the  treatments  were  as  follows : 

Color. — The  color  of  the  lime-sulfur  sprayed  apples  was  brighter 
and  clearer  than  that  of  the  Bordeaux-sprayed  apples. 

Scab. — The  Winesap  is  very  susceptible  to  this  fungus.  The  data 
for  the  unsprayed  trees  show  that  the  percentage  of  injury  due  to  this 
disease  was  very  high,  a  total  of  83  percent  of  the  picked  apples  being 
more  or  less  seriously  affected.  Both  fungicides  varied  somewhat  in 
their  efficiency  in  combating  scab,  but,  in  general,  as  may  be  gathered 
by  a  study  of  Table  31,  Bordeaux  exercised  a  somewhat  superior 
control. 

Sooty  Blotch. — This  disease  was  more  effectively  controlled  by  Bor- 
deaux, partially,  perhaps,  because  of  its  superior  adhesiveness. 

Codling  Moth. — As  in  the  Jonathan  block,  lime  sulfur  arsenate 
of  lead  was  apparently  more  efficient  in  controlling  the  first  brood  of 
codling  moth  than  Bordeaux  arsenate  of  lead. 


146 


BULLETIN  No.  185 


[February, 


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FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


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148  BULLETIN  No.  185  [February, 

Russet. — Bordeaux  caused  much  more  russeting  of  the  fruit  than 
lime  sulfur.  Russeting  tends  to  retard  the  growth  of  the  apple  and  in 
some  cases  renders  it  unsalable,  but,  in  the  ease  of  the  Winesap  vari- 
ety, there  is  a  tendency,  as  the  apple  grows,  for  this  injury  to  be  out- 
grown. The  second  application,  which  is  the  one  immediately  follow- 
ing the  fall  of  the  petals,  caused  the  bulk  of  this  injury,  tho  some 
additional  russeting  followed  the  third  application. 

EFFECTS  OF  USING  LIME  SULFUR  FOR  SOME  APPLICATIONS  AND  BOR- 
DEAUX FOR  OTHER  APPLICATIONS  IN  THE  SAME 
SEASON'S  OPERATIONS 

Table  32  presents  the  data  recorded  on  the  Jonathan  plats  where 
lime  sulfur  was  used  for  some  applications  and  Bordeaux  for  other 
applications  in  the  same  season's  operations.  No  corresponding  ex- 
periments were  made  on  Winesap  trees.  The  results  were  as  follows : 

Scab. — The  two  fungicides  were  about  equally  efficient  in  the  con- 
trol of  scab. 

Sooty  Blotch. — On  the  plats  where  Bordeaux  was  used  for  the 
third  application  there  was  less  sooty  blotch  than  where  lime  sulfur 
was  used. 

Codling  Mofh. — Lime  sulfur  arsenate  of  lead  was  slightly  superior 
to  Bordeaux  arsenate  of  lead  in  the  control  of  the  first  brood  of  cod- 
ling moth. 

Curculio. — The  data  show  no  marked  differences  in  the  control  of 
curculio  by  the  standard  sprays. 

Russeting  and  Foliage  Injury. — Lime  sulfur  caused  much  less  rus- 
seting as  well  as  much  less  foliage  injury.  The  second  application  ap- 
peared to  cause  most  of  the  russeting  of  the  fruit ;  but  foliage  injury 
seemed  to  have  been  produced  in  about  equal  amounts  by  both  the  sec- 
ond and  third  applications.  In  combination  sprays,  where  the  second 
application  was  lime  sulfur  and  the  third  Bordeaux,  or  vice  versa, 
there  was  a  characteristic  russeting  comparable  with  that  which  ap- 
peared where  copper-sulfate  solution  was  mixed  with  lime  sulfur. 
This  russeting  appeared  in  the  form  of  a  black  speckling  or  dotting. 

EFFECTS  OF  DIFFERENT  DILUTIONS  OF  LIME  SULFUR 

Table  33  presents  the  data  recorded  on  the  Winesap  plats  where 
different  dilutions  of  lime  sulfur  were  used.  No  corresponding  experi- 
ments were  conducted  in  the  Jonathan  block. 

Owing  to  the  small  variations  between  the  different  plats,  the  ef- 
fects are  not  described  under  separate  headings.  The  following  facts 
are,  however,  brought  out  by  a  study  of  Table  33 :  first,  the  absence 
of  russeting  where  lime  sulfur  was  used ;  second,  the  control  of  first- 
brood  codling  moth;  third,  the  small  amount  of  sooty  blotch  present 
on  any  of  the  apples  in  the  sprayed  plats  compared  with  the  un- 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


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150  BULLETIN  No.  185  [February, 

sprayed  trees.  The  degree  of  dilution,  within  the  ranges  given  in  the 
table,  made  no  appreciable  difference  in  the  results  obtained  when 
used  for  late  summer  applications. 

EFFECTS  OF  MODERATE  AND  HEAVY  APPLICATIONS  OF  BORDEAUX 

Table  34  presents  the  data  recorded  on  the  Jonathan  plats  where 
moderate  and  heavy  applications  of  Bordeaux  were  used.  These  ex- 
periments were  not  duplicated  in  the  "Winesap  plats.  The  results  were 
as  follows : 

Scab. — An  effective  control  of  scab  resulted  from  both  moderate 
and  heavy  applications  of  Bordeaux. 

Sooty  BloicJi. — Both  moderate  and  heavy  applications  of  Bordeaux 
proved  to  be  extremely  efficient  in  preventing  injury  from  this  fungus. 

Codling  Moth. — In  the  control  of  codling  moth  heavy  applications 
gave  no  better  control  than  moderate  applications. 

Curculio. — A  somewhat  striking  difference  is  to  be  observed  in  the 
relative  control  of  this  insect  exercised  by  the  two  applications  in  fa- 
vor of  the  heavier  application.  In  the  picked  apples,  11  percent  of  all 
the  fruit  was  injured  by  curculio  where  the  heavy  application  was 
made,  whereas  in  the  moderately  sprayed  plat,  28  percent  of  all  the 
fruit  was  affected.  In  the  case  of  the  dropped  apples  19  percent  of 
the  heavily  sprayed  fruit  was  attacked  by  curculio,  whereas  30  per- 
cent of  all  the  fruit  on  the  trees  given  the  moderate  application  was 
injured. 

Russet. — The  heavy  application  of  Bordeaux  resulted  in  the  pro- 
duction of  a  somewhat  larger  number  of  russeted  apples,  and  in  much 
more  severe  russeting  on  the  individual  apples  affected.  The  apples 
on  the  heavily  sprayed  trees  were,  on  the  average,  a  trifle  smaller  than 
those  on  the  lightly  sprayed  trees. 

EFFECTS  OF  MIXED,  NEUTRAL,  AND  ACID  ARSENATES  OF  LEAD  IN 
COMBINATION  WITH  LIME  SULFUR 

Tables  35  and  36  present  the  data  recorded  on  the  Jonathan  and 
Winesap  plats  where  mixed,  neutral,  and  acid  arsenates  of  lead  were 
used  in  combination  with  lime  sulfur.  The  results  were  as  follows : 

Scab. — Table  36  appears  to  show  a  small  but  consistent  lessening 
of  the  amount  of  scab  where  the  acid  arsenate  of  lead  was  added  to 
lime  sulfur.  In  general  the  neutral  and  mixed  arsenates  of  lead  did 
not  add  to  the  effectiveness  of  the  lime  sulfur,  with  which  they  were 
mixed,  in  the  control  of  scab.  The  acid  arsenate  of  lead  was  decidedly 
superior. 

Sooty  Blotcli. — The  addition  of  all  kinds  of  arsenate  of  lead  to 
lime  sulfur  gave  a  spray  superior  to  lime  sulfur  alone  in  the  control 
of  sooty  blotch.  Altho  the  differences  between  the  various  kinds  were 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


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152  BULLETIN  No.  185  [February, 

not  large  there  is  a  fairly  consistent  difference  favoring  first,  the 
mixed  arsenate  of  lead ;  second,  the  acid  arsenate  of  lead ;  and  finally, 
the  neutral  form. 

Codling  Moth. — No  consistent  differences  appeared  in  the  relative 
control  which  the  various  kinds  of  arsenate  of  lead  exercised  over  the 
codling  moth.  All  brands  showed  a  high  degree  of  effectiveness  when 
compared  with  the  plats  sprayed  with  lime  sulfur  alone,  and  with  the 
checks,  which  received  no  spray  whatever. 

Curculio. — The  differences  in  the  control  of  this  insect  as  shown 
by  the  treatments  in  the  various  plats  are  inconsistent.  In  the  Jonathan 
plats  all  sprays  appeared  to  lessen  the  amount  of  injury  from  curculio 
to  a  considerable  extent,  even  lime  sulfur  alone  showing  a  better  degree 
of  control.  In  the  Winesap  block,  however,  the  data  from  which  are  pre- 
sented in  Table  36,  there  was  a  larger  amount  of  injury  from  curculio 
on  the  trees  in  the  lime-sulfur  plat  "than  on  the  trees  in  the  unsprayed 
plat,  indicating  an  irregular  infestation  thruout  the  block.  No  defi- 
nite conclusion  can,  therefore,  be  made  as  to  the  relative  efficiency  of 
the  different  sprays  in  controlling  this  insect. 

Russet. — There  was  no  severe  russet  on  either  the  Jonathan  or  the 
Winesap  apples.  This  may  be  attributed  to  the  fact  that  no  Bordeaux 
was  used  in  the  experiment. 

EFFECTS  OF  MIXED,  NEUTRAL,  AND  ACID  ARSENATES  OF  LEAD  IN 
COMBINATION  WITH  BORDEAUX 

Tables  37  and  38  present  the  data  recorded  on  the  Jonathan  and 
Winesap  plats  where  mixed,  neutral,  and  acid  arsenates  of  lead  were 
used  in  combination  with  Bordeaux.  The  results  were  as  follows : 

Scab. — There  was  no  apparent  difference  in  the  control  of  scab 
which  could  be  attributed  to  the  use  of  the  arsenates  of  lead. 

Codling  Moth. — In  the  Jonathan  block,  the  neutral  arsenate  of  lead 
gave  superior  control,  but  in  the  Winesap  block,  very  little  difference 
in  the  respective  values  of  the  type  is  shown. 

Curculio. — The  three  classes  of  arsenate  of  lead  gave  fairly  equal 
control  of  this  insect,  except  in  Plat  15  in  the  Jonathan  block,  where 
neutral  arsenate  of  lead  was  used. 

Russet. — The  amount  of  russet,  which  was  very  large  in  all  cases  in 
the  Jonathan  block,  did  not  vary  consistently  with  any  one  class  of 
arsenate  of  lead. 


Tables  39  and  40  present  the  data  recorded  on  the  Jonathan  and 
Winesap  plats  where  copper  ferrocyanide  was  used  separately  and  in 
combination  with  arsenate  of  lead.  Data  from  plats  treated  with  Bor- 


1916]                 FIELD  EXPERIMENTS 

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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  155 

deaux  arsenate  of  lead  and  lime  sulfur  arsenate  of  lead  were  included 
in  these  tables  for  comparison.  The  results  were  as  follows : 

Scab. — Copper-ferrocyanide  sprays  were  less  efficient  in  prevent- 
ing injury  from  scab  than  Bordeaux  and  lime-sulfur  sprays.  The  ad- 
dition of  arsenate  of  lead  to  copper  ferrocyanide  appeared  to  increase 
the  fungicidal  value  of  the  spray.  In  the  Winesap  block  the  trees 
sprayed  with  copper  ferrocyanide  alone  were  as  severely  attacked  by 
scab  as  the  unsprayed  trees. 

Sooty  Blotch. — As  in  the  case  of  scab,  the  copper-ferrocyanide 
sprays  proved  less  efficient  in  the  control  of  sooty  blotch  than  either 
Bordeaux  or  lime  sulfur.  The  addition  of  arsenate  of  lead,  however, 
to  copper  ferrocyanide  considerably  increased  the  fungicidal  value  of 
the  spray. 

Codling  Moth. — In  both  the  Jonathan  and  Winesap  blocks  the  cop- 
per-ferrocyanide sprays  were  not  effective  in  controlling  this  insect. 
The  addition  of  arsenate  of  lead  to  the  spray  reduced  the  damage  from 
codling  moth  appreciably,  especially  in  the  Jonathan  block. 

Russet. — There  was  a  noticeable  amount  of  russet  on  the  plats 
sprayed  with  copper  ferrocyanide  and  arsenate  of  lead  in  the  Jona- 
than block.  The  russet  was  less  severe  than  on  the  apples  which  had 
been  sprayed  with  Bordeaux,  but  was  much  more  severe  than  on  the 
apples  sprayed  with  lime  sulfur.  Copper  ferrocyanide  caused  less 
injury  in  the  form  of  russet  on  the  Winesap  apples  than  on  the  Jona- 
thans. The  addition  of  arsenate  of  lead  to  copper  ferrocyanide  in- 
creased the  amount  of  russeting  on  the  Jonathan  apples. 


156  BULLETIN  No.  185  [February, 


SPRAYING  EXPERIMENTS  IN  1911  AT  GRIGGSVILLE, 
PIKE  COUNTY 

BY  ALFEED  J.  GUNDEBSON,  FIRST  ASSISTANT  IN  POMOLOGY 
OBJECTS 

In  the  spraying  work  at  the  Griggsville  station  during  1911,  ex- 
periments were  conducted  to  determine  the  following  points:  (1)  the 
relative  value  of  lime  sulfur  and  Bordeaux  as  summer  sprays;  (2)  the 
value  of  winter  applications  of  lime  sulfur;  (3)  the  relative  effect  of 
light  and  heavy  applications  of  Bordeaux;  (4)  the  means  of  reducing 
injury  following  the  use  of  Bordeaux;  (5)  the  value  of  interchanging 
lime  sulfur  and  Bordeaux  as  summer  sprays ;  (6)  the  value  of  arsenate 
of  lead  as  a  fungicide  when  used  alone  for  controlling  codling  moth ; 
and  (7)  the  value  of  spray  made  by  adding  copper  sulfate  to  lime 
sulfur. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

The  orchard  used  for  these  experiments  belonged  to  Mr.  G.  War- 
ton  and  was  located  one  mile  south  of  Griggsville.  About  one  hundred 
and  sixty  fifteen-year-old  trees  were  used,  which,  with  the  exception 
of  a  few  trees  of  odd  varieties,  consisted  of  Ben  Davis.  They  were 
planted  about  thirty  feet  apart  each  way. 

The  general  vigor  of  the  trees  was  good,  considering  that  they  had 
never  received  any  care.  No  spraying  had  been  done  in  the  orchard ; 
consequently  it  had  never  produced  a  profitable  crop.  The  orchard 
offered  ideal  conditions  for  carrying  on  the  experiment. 

OUTLINE  OP  TREATMENTS 

In  laying  out  these  experiments,  the  orchard  was  divided  into  six- 
teen plats  of  eight  to  eleven  trees  each,  and  a  check  or  unsp rayed  row 
was  left  thru  the  entire  length  of  the  orchard.  These  plats  were 
grouped  and  sprayed  as  nearly  under  the  same  conditions  as  possible, 
especial  care  being  taken  that  the  plats  in  a  given  group  should  be 
strictly  comparable. 

The  plats  in  the  orchard  were  sprayed  as  follows: 


Plat 

Appli- 
cation 

Date 

Treatment 

A 

1 
2 
3 

April    20 
May        9 
May      22 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 
»            )>          »      »       »             ))        »    )> 

B 

1 

2 
3 

April    20 
May       9 
May      22 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 
jj               }  >            >  }       )  }         »                }  >          r  )     )  > 

1916] 


157 


Plat 

Appli- 
cation 

Dat 

e 

Treatment 

G 

1 
2 
3 

April 
May 
May 

20 
9 
22 

Heavy  spraying  with  Bordeaux  arsenate  of  lead 
»           >  >          n           }}             a          n     n 

n           a          >  }           n             n          nn 

D 

1 
2 
3 

April 
May 
May 

20 
9 
22 

Heavy  spraying  with  Bordeaux  arsenate  of  lead 
a           t  t          a           )  >             it          lilt 

E 

1 
2 
3 

April 
May 
May 

20 

9 
22 

Light  spraying  with  Bordeaux  arsenate  of  lead 
it           it          tt           a             a          1  1     1  1 

n           1  1  .        tt           tt             tt          tttt 

P 

1 
2 
3 
4 
5 
6 

April 
May 
May 
June 
June 
July 

20 
10 
23 
1 
12 
25 

Heavy  spraying  with  Bordeaux  arseuate  of  lead 
t  t           t  t          t  t           tt             tt          tt     t  t 

t  t           t  t          tt           tt             tt          tttt 
tt           t  t          tt           tt             it          tttt 
tt           tt          t  t           t  t             tt          tttt 
tt           tt          t  t           tt             tt          tttt 

G 

1 
2 
3 
4 
5 
6 

April 
May 
May 
June 
June 
July 

20 
10 
23 
1 
12 
25 

Heavy  spraying  with  Bordeaux  arsenate  of  lead 

it                       i                  it                    it                       It                  tiii 

a                i             t  i              a           .it             an 
it                t             a              1  1                1  1             tin 
it                t             it              tt                 it             tttt 

Each  application  was  followed  by  a  4-50  solution 
of  lime. 

H 

1 
2 
3 

April 
May 
May 

21 
11 
23 

Heavy  spraying  with  Bordeaux  arsenate  of  lead 

"    lime  sulfur  " 
a             tt            1  1         a          tt        tt            an 

I 

1 
2 

April 
May 

21 
11 

Heavy  spraying  with  Bordeaux  arsenate  of  lead 

3 

May 

J 

1 
2 
3 

April 
May 
May 

21 
11 
23 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 
"            "          "     Bordeaux      " 

tt               it             a              it                 it                an 

K 

1 

2 
3 

April 
May 
May 

21 
23 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 
"            "          "  Bordeaux            "        "    " 

L 

1 

2 
3 

April 
May 
May 

21, 

10 
24 

Heavy  spraying  with  Bordeaux  arsenate  of  lead 

"                       "     arsenate  of  lead 
1  1             a            it             a          it 

M 

1 

2 
3 

April 
May 
May 

21 
10 

24 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead  . 
'     arsenate  of  lead 
"            "          "    arsenate  of  lead 

N 

1 

2 
3 

April 

May 
May 

21 

12 

24 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 

plus  4  pounds  copper  sulfate  to  100  gallons 
tt              a            a       a         it                a          tin 

a              a            a       tt         it                n          1111 

O 

1 

2 
3 

April 

May 
May 

21 

12 
24 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 

plus  8  pounds  copper  sulfate  to  100  gallons 
n              it            n       n         n                n          an 

11               n             it        n         n                n          nil 

P 

1 

2 
3 

April 

May 
May 

21 
24 

Heavy  spraying  with  lime  sulfur  arsenate  of  lead 
plus  12  pounds  copper  sulfate  to  100  gallons 

n              a            a       n         n                n          an 

Check 

none 

No  treatment 

NOTE. — All  plats  except  B  and  C  received  a  winter  application  of  lime  sulfur, 
April  10-14. 


158 


BULLETIN  No.  185 


[February, 


Ben  Davis          (ft**611  E8^13  ^^  Other  varieties 

CHART  10. — PLAN  OF  PLATS  IN  ORCHARD  OF  MR.  G.  WARTON,  GRIGGSVILLE,  1911 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  159 

APPARATUS  AND  PREPARATION  OF  MATERIALS 

In  all  cases  where  Bordeaux  was  used  it  was  made  according  to 
the  standard  formula :  8  pounds  of  copper  sulf ate  and  8  pounds  of 
lime  to  100  gallons  of  water.  The  lime  sulfur  was  made  according  to 
the  Illinois  formula:  50  pounds  of  lime  and  100  pounds  of  sulfur 
boiled  together  in  66  gallons  of  water  until  all  the  sulfur  was  in  solu- 
tion. For  winter  strength,  lime  sulfur  was  used  at  the  rate  of  1  gal- 
lon in  7  gallons  of  water  (approximately  20  pounds  of  sulfur  in  100 
gallons)  ;  for  summer  strength,  it  was  used  at  the  rate  of  1  gallon  in 
18  gallons  of  water  (approximately  8  pounds  of  sulfur  in  100  gallons). 
Grasselli  arsenate  of  lead  paste  was  used  at  the  rate  of  4  pounds  to  100 
gallons  of  spray.  All  plats  except  B  and  C  received  a  winter  applica- 
tion of  lime  sulfur.  Each  plat  also  received  three  summer  sprays. 
Application  No.  1  was  made  in  the  cluster-bud  or  pink  stage ;  No.  2  was 
made  at  the  dropping  of  the  petals;  and  No.  3  was  made  about  two 
weeks  later.  In  addition  to  the  three  summer  sprays  above  referred  to, 
Plats  F  and  G  received  three  extra  summer  sprays. 

The  winter  spray  of  lime  sulfur  was  applied  with  a  200-gallon 
Gould  hand  outfit,  at  about  150  pounds  pressure.  The  summer  sprays 
were  applied  with  a  50-gallon  Gould  barrel  oufit,  at  about  150  pounds 
pressure.  In  all  the  spraying,  double  Vermorel  nozzles  were  used.  All 
plats,  except  where  noted  otherwise,  were  sprayed  heavily;  every  part 
of  the  tree  received  a  thoro  application. 

CHARACTER  OP  RECORDS  AND   METHOD   OF   MAKING 

During  the  season,  records  were  kept  of  all  items  of  importance. 
These  records  included  the  appearance  of  the  foliage  thruout  the  sea- 
son in  regard  to  fungi,  insects,  spray,  and  vigor.  Dropped  apples 
were  collected,  counted,  and  examined  for  various  injuries.  At  pick- 
ing time  two  representative  trees  from  each  sprayed  plat  and  two  from 
the  unsprayed  plats  were  chosen  and  used  in  obtaining  the  data.  Two 
hundred  apples  were  selected  from  different  parts  of  each  tree  and 
examined  carefully.  The  results  from  the  two  trees  in  each  plat  were 
averaged  together,  this  average  being  taken  to  represent  the  value  of 
the  treatment.  Records  from  the  unsprayed  trees  were  made  in  the 
same  manner.  All  the  apples  from  each  tree  in  each  plat  and  from 
each  tree  in  the  check  row  were  counted,  weighed,  and  sorted  in  No. 
1  's,  No.  2  's,  and  culls. 

The  No.  1  Ben  Davis  were  not  less  than  2y2  inches  in  diameter, 
were  free  from  scab,  with  only  a  slight  amount  of  insect  or  other  in- 
juries, and  of  good  shape  and  color.  No.  2  apples  were  2*4  inches  in 
diameter,  occasionally  with  slight  scab,  and  with  not  over  20  percent 
of  the  apples  injured  to  a  slight  extent  by  insects  and  other  causes; 


160  BULLETIN  No.  185  [February, 

they  were  of  good  shape  and  color.    Apples  below  these  qualifications 
were  classed  as  culls. 

WEATHER  CONDITIONS 

The  weather  from  the  latter  part  of  April  until  September  was  ex- 
ceptionally hot  and  dry.  The  trees  were  in  bloom  May  1,  and  the  still, 
sultry  days  and  nights  at  that  time  presented  ideal  conditions  for  set- 
ting of  the  fruit.  All  the  trees  set  a  good  crop  and  were  heavily 
loaded  at  picking  time. 

Under  the  dry  conditions  of  the  spring  and  summer,  very  little 
scab  developed  even  on  the  unsprayed  orchards  in  the  vicinity.  Sep- 
tember and  October,  however,  were  unusually  wet,  and  during  that 
time  sooty  blotch  developed  in  great  abundance  and  caused  severe 
damage,  especially  to  unsprayed  fruit.  At  the  end  of  the  season,  the 
foliage  on  the  unsprayed  trees  in  the  experimental  orchard  was  al- 
most as  healthy  in  appearance  as  the  foliage  on  the  sprayed  trees. 

VALUE  OP  A  DORMANT-TREE  APPLICATION  OF  LIME  SULFUR,  AND  RELA- 
TIVE VALUE  OF  LIME  SULFUR  AND  BORDEAUX  AS  SUMMER  SPRAYS 

Spraying  with  lime  sulfur  while  the  trees  are  dormant  is  the 
standard  treatment  for  San  Jose  scale.  Many  growers,  however,  ap- 
ply this  spray  whether  an  orchard  has  scale  or  not,  believing  that  trees 
sprayed  with  lime  sulfur  while  dormant  suffer  less  from  scab  during 
the  following  season  than  those  which  are  not  so  sprayed. 

To  determine  the  value  of  a  dormant-tree  application  of  lime  sul- 
fur, and  also  to  learn  the  relative  value  of  lime  sulfur  and  Bordeaux 
as  summer  sprays,  four  plats  were  treated  as  follows : 

Plat  A:  Lime  sulfur  arsenate  of  lead,  1st,  2d,  and  3d  applications  (with 
dormant -tree  application  of  lime  sulfur). 

Plat  B:  Lime  sulfur  arsenate  of  lead,  1st,  2d,  and  3d  applications  (with- 
out dormant-tree  application  of  lime  sulfur). 

Plat  C:  Bordeaux  arsenate  of  lead,  1st,  2d,  and  3d  applications  (without 
dormant-tree  application  of  lime  sulfur). 

Plat  D:  Bordeaux  arsenate  of  lead,  1st,  2d,  and  3d  applications  (with  dor- 
mant-tree application  of  lime  sulfur). 

EFFECT  ON  FOLIAGE 

The  foliage  of  Plats  A,  B,  C,  and  D  was  practically  free  from  scab 
during  the  entire  season.  A  slight  amount  of  scab  appeared  on  the 
unsprayed  trees  about  May  20,  but  at  no  time  during  the  summer  was 
the  infection  serious ;  in  fact,  it  was  negligible.  No  apparent  differ- 
ence could  be  noted  between  the  foliage  of  Plat  A,  which  received  a 
dormant-tree  application  of  lime  sulfur,  and  Plat  B,  which  did  not, 
for  both  plats  appeared  equally  vigorous  and  free  from  scab.  The 
same  was  true  of  Plats  C  and  D,  and  indicated  that  under  the  con- 
ditions in  this  orchard  a  dormant-tree  application  of  lime  sulfur  was 
useless. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  161 

Plats  A  and  B,  which  received  three  summer  applications  of  lime 
sulfur,  and  Plats  C  and  D,  which  were  sprayed  three  times  with  Bor- 
deaux, suffered  little  from  scab.  Early  in  the  summer  a  very  slight 
amount  of  lime-sulfur  injury  appeared  on  the  foliage  of  Plats  A  and 
B.  No  appreciable  amount  of  Bordeaux  injury  was  noticed  on  the 
foliage  of  Plats  C  and  D  until  the  latter  part  of  September,  when 
this  spray  caused  the  trees  to  lose  a  considerable  number  of  leaves. 
On  the  whole,  Plats  A  and  B,  which  were  sprayed  with  lime  sulfur, 
had  denser  and  more  vigorous-looking  foliage  and  retained  it  longer 
than  Plats  C  and  D,  which  were  sprayed  with  Bordeaux. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  20,  and  the  results  are  presented  in  Table  41. 

This  table  shows  that  the  dormant-tree  application  of  lime  sulfur 
had  no  effect  on  apple  scab,  for  it  is  evident  that  the  amount  of  scab 
on  Plat  A  was  practically  the  same  as  on  Plat  B,  and  this  is  also  true 
for  Plats  C  and  D. 

The  results  also  show  that  Bordeaux  was  slightly  superior  to  lime 
sulfur  in  the  control  of  apple  scab,  but  the  difference  is  so 
slight  that  the  two  may  fairly  be  considered  to  have  been  equal 
in  effectiveness.  The  unsprayed  row  shows  only  12.37  percent  slight 
scab,  which  is  a  small  amount  of  infection  for  unsprayed  apples.  This 
may  be  explained  by  the  fact  that  the  spring  and  summer  were  ex- 
ceedingly dry  and  offered  conditions  unfavorable  to  scab  development. 

There  was  a  difference,  however,  between  the  amounts  of  fly  speck 
and  sooty  blotch  on  Plats  A  and  B  and  Plats  C  and  D.  Plats  A  and 
B,  sprayed  with  lime  sulfur,  showed  19.75  and  22.25  percent  flyspeck 
and  23.5  and  19.25  percent  sooty  blotch,  respectively,  as  compared 
with  Plats  C  and  D,  sprayed  with  Bordeaux,  which  showed  but  .25 
and  4  percent  flyspeck,  and  .5  and  4  percent  sooty  blotch.  The  un- 
sprayed row,  however,  showed  63.87  percent  flyspeck  and  52  percent 
sooty  blotch.  It  is  probable  that  a  difference  in  adhesiveness  in  favor 
of  Bordeaux  over  lime  sulfur  explains  this  difference  in  control. 

The  amount  of  codling  moth  on  sprayed  plats  and  on  the  check 
row  was  small.  The  amount  of  curculio  injury  was  greater  for  the 
lime-sulfur  plats  than  for  the  Bordeaux  plats. 

A  very  important  difference  between  the  effects  of  these  sprays 
upon  the  fruit  is  shown  in  the  russet  columns.  Plat  C,  sprayed  with 
Bordeaux,  had  .5  percent  serious  and  41.75  percent  slight  russet,  and 
Plat  D,  sprayed  with  Bordeaux,  had  37.25  percent  slight  russet.  Plats 
A  and  B,  sprayed  with  lime  sulfur,  gave,  on  the  other  hand,  only  2.25 
and  4  percent  slight  russet,  respectively.  Plats  A  and  B  also  snowed 
but  a  negligible  amount  of  lime-sulfur  burn. 


162 


BULLETIN  No.  185 


[February, 


Percentage  of  picked  apples  affected  by 

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Lime  sulfur  arsenatc  of  lead  wi 
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Lime  sulfur  arsenate  of  lead 
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Bordeaux  arsenate  of  lead  witho 
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Bordeaux  arsenate  of  lead  with 
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No  treatment  

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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  163 

Plats  A  and  B  had  79  and  69  percent  No.  1  *s,  18  and  28  percent 
No.  2's,  and  3  and  3  percent  culls,  respectively.  Plats  C  and  D  gave 
71  and  74  percent  No.  1's,  26  and  24  percent  No.  2's,  and  3  and  2  per- 
cent culls,  respectively.  The  unsp rayed  row  had  65  percent  No.  1's, 
31  percent  No.  2's,  and  4  percent  culls,  which  was  very  exceptional 
for  unsprayed  apples.  Flyspeck,  sooty  blotch,  and  curculio  were  in- 
strumental in  reducing  the  percentage  of  No.  1  apples  on  Plats  A  and 
B,  while  curculio  and  russet  caused  the  reduction  on  Plats  C  and  D. 

There  was  a  marked  difference  between  the  lime-sulfur  and  Bor- 
deaux apples.  Those  sprayed  with  lime  sulfur  were  larger,  smoother, 
and  had  better  color  and  a  more  waxy  finish  than  those  sprayed  with 
Bordeaux. 

LIGHT  VERSUS  HEAVY  APPLICATIONS  OF  BORDEAUX 

There  has  been  some  question  as  to  whether  or  not  the  amount  of 
Bordeaux  injury  is  proportional  to  the  quantity  of  spray  applied. 
To  determine  the  relative  effect  of  light  and  heavy  applications  of 
Bordeaux,  two  plats  were  treated  as  follows : 

Plat  D:     Bordeaux  arsenate  of  lead  (heavy). 
Plat  E:     Bordeaux  arsenate  of  lead  (light). 

EFFECT   ON   FOLIAGE 

Both  light  and  heavy  applications  controlled  scab  on  the  foliage 
effectively.  The  appearance  of  the  foliage  of  Plats  D  and  E  was  very 
similar  until  the  latter  part  of  September,  when  Bordeaux  injury  be- 
gan to  appear  on  Plat  D.  This  injury  reduced  the  amount  of  foliage 
materially.  Plat  E,  however,  suffered  no  appreciable  amount  of  in- 
jury. This  difference  indicates  that  the  amount  of  Bordeaux  injury 
to  foliage  was  more  or  less  proportional  to  the  quantity  of  spray  ap- 
plied. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  20  to  23 ;  the  results  are  presented  in  Table  42. 

Table  42  shows  that  heavy  and  light  applications  of  Bordeaux  were 
equally  effective  in  the  control  of  scab,  .5  percent  slight  scab  appear- 
ing on  both  plats.  Plat  E,  given  the  light  application,  however, 
showed  26.5  percent  flyspeck  and  18.75  percent  sooty  blotch  as  com- 
pared to  4  percent  flyspeck  and  4  percent  sooty  blotch  on  Plat  D, 
which  was  given  the  heavy  application.  Plat  D  showed  only  1.25  per- 
cent affected  by  codling  moth  and  29.75  percent  by  curculio,  as  com- 
pared with  Plat  E  with  5.75  percent  cocuing-moth  and  43  percent  cur- 
culio injury.  It  is  evident  from  this  that  better  control  of  flyspeck. 
sooty  blotch,  codling  moth,  and  curculio  was  obtained  where  Bordeaux 
arsenate  of  lead  was  applied  heavily. 


164  BULLETIN  No.  185  [February, 

There  was,  however,  less  russet  on  Plat  E,  which  received  light 
applications  of  Bordeaux,  than  on  Plat  D,  which  was  sprayed  heavily. 
Plat  E  showed  18.75  percent  slight  russet  as  compared  with  Plat  D 
with  37.25  percent  slight  russet. 

Each  plat  had  very  nearly  the  same  percentage  of  No.  1's,  No.  2's, 
and  culls. 

The  apples  from  Plat  E,  which  was  sprayed  lightly  with  Bordeaux, 
had  better  color  than  those  from  Plat  D,  which  received  heavy  appli- 
cations of  Bordeaux. 

ATTEMPTS  TO  REDUCE  BORDEAUX  INJURY 

It  has  been  suggested  that  by  keeping  fruit  and  foliage  continually 
coated  with  the  spray,  Bordeaux  injury  might  be  reduced.  Previous, 
experiments  have  shown  that  a  solution  of  milk  of  lime  applied  soon 
after  the  Bordeaux  application  became  dry  reduced  injury  to  foliage.1 
In  order  to  determine  the  practical  application  of  these  methods,  the 
following  experiment  was  conducted : 

Plat  D:     Bordeaux  arsenate  of  lead  (heavy),  1st,  2d,  and  3d  applications. 

Plat  F:  Bordeaux  arsenate  of  lead  (heavy),  1st,  2d,  and  3d  applications, 
followed  by.  three  additional  applications. 

Plat  G:  Bordeaux  arsenate  of  lead  (heavy),  1st,  2d,  and  3d  applications, 
followed  by  three  additional  applications  of  4^50  lime  solution. 

EFFECT   ON  FOLIAGE 

Scab  was  effectively  controlled  on  the  foliage  of  Plats  D,  F,  and  G. 
No  Bordeaux  injury  to  foliage  occurred  until  late  in  September.  The 
amount  of  injury  at  that  time  was  about  equal  on  all  three  plats. 
The  foliage  of  all  plats  dropped  prematurely,  as  compared  with  plats 
not  sprayed  with  Bordeaux.  The  foliage  of  Plat  F,  which  was  kept 
well  coated  with  Bordeaux  until  late  in  the  summer,  was  no  better 
nor  freer  from  Bordeaux  injury  than  Plat  D,  which  received  the  three 
regular  applications  only.  The  foliage  on  Plat  G,  which  was  sprayed 
the  same  number  of  times  as  Plat  F,  and  where  each  Bordeaux  appli- 
cation was  followed  by  one  of  milk  of  lime,  was  no  better  than  the 
foliage  of  Plat  F,  which  did  not  receive  the  milk  of  lime,  nor  was  it 
any  better  than  Plat  D,  which  received  the  three  regular  applications 
only. 

EFFECT   ON  FRUIT 

The  apples  from  Plats  D,  F,  and  G  were  picked,  sorted,  and  ex- 
amined October  20  to  21,  and  the  results  are  presented  in  Table  43. 

These  results  show  that  scab  was  completely  controlled  on  Plats 
F  and  G,  which  received  respectively  six  applications  of  Bordeaux 
with  and  without  applications  of  milk  of  lime  following.  Plat  D, 
which  received  the  three  regular  applications  only,  showed  but  .5  per- 
cent slight  scab.  Flyspeck  and  sooty  blotch  were  effectively  controlled 

aC.  S.  Crandall,  111.  AST.  Exp.  Sta.  Bui.  135.  p.  280  (1909). 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS        .  165 

on  Plat  D,  and  were  absolutely  controlled  on  Plats  F  and  G.  Codling- 
moth  injury  to  all  plats  was  very  slight.  All  sprays  reduced  the 
amount  of  curculio  injury  materially. 

A  very  interesting  difference  between  the  effects  of  these  sprays 
upon  the  fruit  is  shown  in  the  russet  column.  Plat  D,  which  received 
three  regular  applications  of  Bordeaux,  shows  37.25  percent  slight 
russet;  Plat  F,  sprayed  six  times  with  Bordeaux,  shows  35.25  per- 
cent slight  russet.  In  other  words,  spraying  so  as  to  maintain  a  coat- 
ing of  Bordeaux  was  of  no  value  in  reducing  injury  to  the  fruit.  Plat 
G,  sprayed  the  same  number  of  times  with  Bordeaux  as  Plat  F,  but 
treated  with  an  application  of  milk  of  lime  after  each  Bordeaux  spray, 
shows  56.25  percent  slight  russet.  It  would  appear  from  these  rec- 
ords that  the  increased  amount  of  russet  on  Plat  G,  as  compared  with 
that  on  Plat  F,  was  due  to  the  lime  applications, — a  rather  unlooked- 
for  result.  Bordeaux  injury  to  fruit  may  be  the  result  of  too  high 
pressure.  It  is  possible  that  the  small  particles  of  lime  in  Bordeaux 
or  in  milk  of  lime  may,  under  certain  pressures  and  conditions,  injure 
the  cuticle  of  apples  by  permitting  the  entrance  of  soluble  copper  to 
the  cells  of  the  skin  of  the  apple,  thus  causing  russet.  The  increase  in 
the  amount  of  russet  on  Plat  G,  as  compared  with  Plat  F,  may  have 
been  due  to  the  applications  of  milk  of  lime  following  the  Bordeaux 
sprays.  Plat  G,  however,  produced  a  higher  percentage  of  No.  1 
apples  than  did  Plats  D  and  F. 

The  fruits  from  all  plats  lacked  color  and  finish.  Tho  the  russet 
on  the  apples  was  slight,  it  was,  nevertheless,  very  noticeable  and  gave 
the  fruit  a  rough  finish. 

VALUE  OF  INTERCHANGING  LIME  SULFUR  AND  BORDEAUX 
As  SUMMER  SPRAYS 

It  has  generally  been  thought  that  Bordeaux  russeting  accompanies 
sprays  applied  soon  after  the  setting  of  the  fruit.  It  has  been  sug- 
gested, therefore,  that  lime  sulfur  might  be  substituted  for  Bordeaux 
at  this  critical  time.  With  the  hope  that  a  method  might  be  determined 
which  would  do  away  with  russeting  of  the  fruit  and  injury  to  foliage, 
and  which  would  at  the  same  time  control  fungous  diseases,  plats  were 
treated  as  follows : 

Plat  A:     Lime  sulfur  arsenate  of  lead,  1st,  2d,  and  3d  applications. 
Plat  D:     Bordeaux  arsenate  of  lead,  1st,  2d,  and  3d  applications. 
Plat  H:     Bordeaux  arsenate  of  lead,  1st  application;  lime  sulfur  arsenate  of 
lead,  2d  and  3d  applications. 

Plat  I:  Bordeaux  arsenate  of  lead,  1st  and  2d  applications;  lime  sulfur  ar- 
senate of  lead,  3d  application. 

Plat  J:  Lime  sulfur  arsenate  of  lead,  1st  application;  Bordeaux  arsenate  of 
lead,  2d  and  3d  applications. 

Plat  K:  Lime  sulfur  arsenate  of  lead,  1st  and  2d  applications;  Bordeaux 
arsenate  of  lead,  3d  application. 


166 


BULLETIN  No.  185 


[February, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  167 

EFFECT  ON  FOLIAGE 

During  the  entire  season  practically  no  scab  appeared  on  the  foli- 
age of  Plats  H,  I,  J,  and  K.  The  foliage  of  all  these  plats  was  equally 
vigorous  thruout  the  entire  season,  with  the  exception  of  a  slight 
amount  of  Bordeaux  injury  which  appeared  on  Plats  J  and  K  toward 
the  end  of  the  season. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  20,  25,  and  26,  and  the  results  are  presented  in  Table  44. 

All  sprays  controlled  scab  almost  completely,  but  flyspeck  and 
sooty  blotch  were  not  so  satisfactorily  prevented.  Plat  H  had  20 
percent  flyspeck  and  25.75  percent  sooty  blotch;  Plat  I  had  9  per- 
cent flyspeck  and  14  percent  sooty  blotch ;  Plat  J,  8  percent  flyspeck 
and  18.5  percent  sooty  blotch ;  and  Plat  K,  13.25  percent  flyspeck  and 
14  percent  sooty  blotch.  These  results,  therefore,  indicate  that  where 
Bordeaux  was  used  a  greater  number  of  times  than  lime  sulfur,  the 
amount  of  flyspeck  and  sooty-blotch  infection  was  less.  Codling-moth 
injury  was  very  slight  on  all  these  plats,  even  on  the  unsprayed  row. 
Curculio  injury  was  reduced  to  some  extent  on  all  sprayed  trees  as 
compared  with  the  unsprayed  trees. 

Plat  H,  which  received  Bordeaux  for  the  first  spray  and  lime  sul- 
fur for  the  second  and  third,  showed  17  percent  slight  russet.  By 
subtracting  from  this  amount  2.25  percent,  which  was  the  amount  of 
slight  russet  shown  on  Plat  A,  sprayed  three  times  with  lime  sulfur, 
it  is  found  that  Bordeaux  at  the  first  application  caused  14.75  percent 
slight  russet.  As  may  be  noted,  no  russet  appeared  on  the  unsprayed 
row.  Plat  I,  sprayed  with  Bordeaux  for  the  first  and  second  appli- 
cations and  with  lime  sulfur  for  the  third,  showed  49.5  percent  slight 
russet.  Since  14.75  percent  slight  russet  has  been  attributed  to  the 
first  application  of  Bordeaux,  this  amount  deducted  from  49.5  per- 
cent slight  russet  leaves  34.75  percent  slight  russet  due  to  the  second 
Bordeaux  and  the  third  lime-sulfur  sprays.  Sprays  1,  2,  and  3  together 
caused  only  2.25  percent  injury  when  lime  sulfur  was  used  thruout. 
Therefore,  at  least  32.5  percent  of  the  russet  may  be  attributed  to  the 
second  application  of  Bordeaux.  Plat  J  showed  39.5  percent  slight  rus- 
set. It  has  just  been  stated  that  32.5  percent  slight  russet  came  from 
the  second  application  of  Bordeaux.  By  subtracting  this  amount  from 
39.5  percent,  the  amount  of  slight  russet  shown  on  Plat  J,  it  is  found 
that  the  third  application  of  Bordeaux  caused  only  7  percent  slight 
russet.  Plat  K,  which  received  lime  sulfur  for  the  first  and  second 
applications  and  Bordeaux  for  the  third,  showed  9.5  percent  slight 
7-usset,  2.25  percent  of  which  was  caused  by  lime  sulfur,  the  balance 
7  percent  having  been  caused  by  Bordeaux.  To  sum  up  the  discus- 
sion on  russet,  these  results  show  that  the  greatest  amount  of  russeting 


168  BULLETIN  No.  185  [February, 

from  Bordeaux  occurred  at  the  second  application,  and  that  a  small 
amount  came  from  both  the  cluster-bud  spray  and  the  spray  applied 
two  weeks  after  the  fall  of  the  petals.  A  negligible  amount  of  lime- 
sulfur  burn  occurred  on  Plats  H  and  K. 

Plats  H  and  A  produced  the  highest  percentages  of  No.  1  apples. 
The  fruit  from  Plat  H  had  the  best  color,  altho  the  apples  from  all 
of  these  plats  had  good  color  and  fair  finish. 

ARSENATE  OF  LEAD  ALONE  AS  A  FUNGICIDE 

To  determine  the  fungicidal  value  of  arsenate  of  lead  alone  when 
used  primarily  as  a  spray  for  codling  moth,  plats  were  sprayed  as 
follows : 

Plat  L:  Bordeaux  arsenate  of  lead,  1st  application;  arsenate  of  lead,  2d 
and  3d  applications. 

Plat  M:  Lime  sulfur  arsenate  of  lead,  1st  application;  arsenate  of  lead,  2d 
and  3d  applications. 

EFFECT  ON  FOLIAGE 

No  appreciable  amount  of  scab  appeared  on  the  foliage  of  Plats 
L  and  M.  The  foliage  was  very  vigorous  during  the  entire  season, 
and  practically  no  foliage  injury  resulted  from  the  use  of  the  sprays. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  20  and  25,  and  the  results  are  presented  in  Table  45. 

These  results  show  that  the  sprayings  given  Plats  L  and  M  were 
effective  in  controlling  scab.  Plat  L  had  14  percent  flyspeck  and  24.5 
percent  sooty  blotch  as  compared  with  Plat  M  with  21  percent  flyspeck 
and  35  percent  sooty  blotch.  It  is  evident  that  arsenate  of  lead  ap- 
plied at  the  second  and  third  applications  had  little  effect  on  these 
diseases.  The  results  seem  to  show  that  lime  sulfur  arsenate  of  lead 
and  Bordeaux  arsenate  of  lead  applied  at  the  first  spraying  reduced 
the  amount  of  flyspeck  and  sooty-blotch  infection,  but  that  arsenate 
of  lead  alone  applied  at  the  second  and  third  applications  had  little 
or  no  fungicidal  value. 

Codling-moth  and  curculio  infestation  was  reduced  on  both  plats. 
Plat  L  showed  10.5  percent  slight  russet,  and  Plat  M  only  1.25  percent 
slight  russet.  It  is  evident,  in  the  case  of  Plat  L,  that  the  russet  was 
caused  by  the  Bordeaux,  which  was  used  at  the  first  application. 

The  fruit  from  both  Plats  L  and  M  had  excellent  color  and  finish, 
exceeding  in  this  respect  the  apples  from  any  of  the  other  plats  in 
the  orchard.  It  was  evident  that  the  arsenate  of  lead  stimulated  color. 
Plat  M  had  84  percent  No.  1's  and  Plat  L,  77  percent  of  the  same 
grade. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


169 


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Treatment 

Lime  sulfur  arsenate  of  lead  with  4-100 
copper  sulf  ate  
Lime  sulfur  arsenate  of  lead  with  8-100 
copper  sulf  ate  
Lime  sulfur  arsenate  of  lead  with  12-100 
copper  sulf  ate  
Lime  sulfur  arsenate  of  lead  
No  treatment  

03 

£       O       AH       <J^ 

170  BULLETIN  No.  185  [February, 

ADDING  COPPER  SULFATE  TO  LIME  SULFUR 

To  determine  the  value  of  adding  copper  sulfate  to  lime  sulfur, 
plats  were  sprayed  as  follows : 

Plat  N :  Lime  sulfur  arsenate  of  lead  4-  4  pounds  of  copper  sulfate  to  100  gallons 
Plat  O  •       "        "  "  "U8       "       "       "          "  "         " 

Plat  P  •      "        "  "  "    -1-12       "       "       "          "  "         " 

Plat  A:      "        "  "  " 

EFFECT   ON  FOLIAGE 

When  copper  sulfate  was  added  to  the  dilute  lime  sulfur,  the  re- 
sulting mixture  appeared  dark  brown  in  color.  After  drying  on  the 
foliage  and  fruit,  it  appeared  black.  The  spray  was  remarkably  ad- 
hesive, showing  noticeably  on  both  fruit  and  foliage  at  picking  time. 

The  foliage  of  Plats  N,  0,  and  P  was  practically  free  from  scab 
during  the  entire  season.  No  foliage  injury  resulted  from  the  use  of 
the  sprays.  The  foliage  was  by  far  the  best  of  any  in  the  orchard. 
It  appeared  more  dense  and  possessed  a  darker  green  color  than  any 
other. 

EFFECT   ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  24 ;  the  results  are  presented  in  Table  46. 

These  results  show  that  all  the  sprays  on  Plats  N,  0,  and  P  con- 
trolled scab  perfectly.  Plat  P  showed  2.75  percent  flyspeck  and  8.5 
percent  sooty  blotch,  as  compared  with  Plat  O  with  16.25  percent  fly- 
speck  and  20.5  percent  sooty  blotch,  and  Plat  N  with  9.5  percent  fly- 
speck  and  8.75  percent  sooty  blotch.  Curculio  injury  was  slightly  re- 
duced on  all  plats.  Codling-moth  injury  was  small  on  the  sprayed 
and  unsprayed  plats. 

The  amount  of  russet  on  these  plats  increased  with  the  amount  of 
copper  sulfate  in  one  hundred  gallons  of  the  sprays.  Plat  N,  with  4 
pounds  of  copper  sulfate  to  100  gallons,  had  21.5  percent  slight  rus- 
set; Plat  0,  with  8  pounds  of  copper  sulfate  to  100  gallons,  37.25 
percent  slight  russet;  and  Plat  P,  with  12  pounds  of  copper  sulfate 
to  100  gallons,  53  percent  slight  russet.  These  results  show  that  the 
amount  of  russet  increased  with  the  amount  of  copper  sulfate  in  the 
sprays.  This  russet  differed  from  ordinary  Bordeaux  russet,  appear- 
ing in  the  form  of  small  dark  specks.  The  amount  of  lime-sulfur  burn 
on  Plats  0  and  P  was  negligible. 

Plat  P  had  83  percent  of  No.  1  apples,  Plat  N,  80  percent,  and 
Plat  0,  73  percent.  The  fruit  from  all  three  plats  had  good  color  but 
was  a  little  rough  in  finish. 

SUMMARY  OF  RESULTS  AT  GRIGGSVILLE,  1911 

1.  Conditions  at  the  Griggsville  station  during  1911  were  un- 
favorable for  the  development  of  scab.  Unsprayed  orchards  in  this 
vicinity  were  practically  free  from  this  fungus. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  171 

2.  Under  these  conditions,  a  winter  application  of  lime  sulfur 
was  of  no  value  in  the  control  of  scab  and  had  no  beneficial  effect  on 
the  trees. 

3.  Homemade  lime  sulfur,  containing  8  pounds  of  sulfur  in  100 
gallons  of  spray  along  with  4  pounds  of  arsenate  of  lead,  proved  equal 
to  Bordeaux  arsenate  of  lead,  8-8-4-100,  in  controlling  scab.    Bordeaux, 
however,  gave  better  results  than  lime  sulfur  in  the  control  of  fly- 
speck  and  sooty  blotch. 

4.  Three  applications  of  Bordeaux  arsenate  of  lead  caused  injury 
to  foliage  and  russeted  the  fruit,  while  lime  sulfur  arsenate  of  lead 
caused  practically  no  russet  and  no  foliage  injury. 

5.  Trees  sprayed  with  lime  sulfur  arsenate  of  lead  had  better 
foliage  and  the  fruit  possessed  higher  color  and  finish  than  those 
sprayed  with  Bordeaux  arsenate  of  lead. 

6.  A  light  application  of  Bordeaux  caused  less  foliage  injury  and 
russeting  of  the  fruit  than  a  heavy  application. 

7.  Maintaining  a  coating  on  fruit  and  foliage  caused  no  reduction 
in  the  amount  of  injury  to  either.    Applying  an  8-100  milk-of-lime 
to  trees  sprayed  with  Bordeaux,  as  soon  as  the  Bordeaux  was  dry,  did 
not  reduce  the  amount  of  injury  to  foliage,  while  it  did  increase  the 
amount  of  russet  on  the  fruit. 

8.  Russeting  of  the  fruit  resulted  from  each  of  the  three  appli- 
cations of  Bordeaux.    Most  of  the  russeting,  however,  occurred  at  the 
second  application,  which  was  made  immediately  after  the  fall  of 
the  petals. 

9.  Arsenate  of  lead  alone  had  practically  no  fungicidal  value. 

10.  Lime-sulfur   solutions,   to  which  were  added  4,   8,   and   12 
pounds  of  copper  sulfate  to  100  gallons,  controlled  scab  perfectly,  and 
gave  a  very  dense  green  foliage.    The  sprays  caused  considerable  rus- 
seting of  the  fruit,  the  severity  varying  with  the  amount  of  copper 
sulfate  in  each. 

11.  The  best  colored  and  best  finished  apples  were  produced  on 
the  plats  which  were  sprayed  with  arsenate  of  lead  alone  at  the  sec- 
ond and  third  applications,  indicating  that  arsenate  of  lead  has  a 
stimulating  effect  on  color. 


172 


BULLETIN  No.  185 


[February, 


SPRAYING  EXPERIMENTS  IN  1912  AT  GRIGGSVILLE, 
PIKE  COUNTY 

BY  ALFEED  J.  GUNDEESON 
OBJECTS 

In  the  spraying  work  at  the  Griggsville  station  during  1912,  experi- 
ments were  conducted  to  determine  the  following  points:  (1)  the 
relative  value  of  lime  sulfur  and  Bordeaux;  (2)  the  value  of  inter- 
changing lime  sulfur  and  Bordeaux  as  summer  sprays;  (3)  the  fungi- 
cidal  and  insecticidal  value  of  various  strengths  of  copper  ferro- 
cyanide;  (4)  the  effect  of  the  addition  of  arsenate  of  lead  to  lime  sul- 
fur; and  (5)  the  relative  values  of  various  strengths  of  lime  sulfur. 

LOCATION  AND  DESCRIPTION  OF  ORCHARD 

For  these  experiments  the  orchard  used  belonged  to  Mr.  F.  Turn- 
bull,  located  three  and  one-half  miles  southeast  of  Griggsville.  Two 
hundred  and  six  fourteen-year-old  trees  were  chosen,  which,  with  the 
exception  of  a  few  trees  of  odd  varieties,  were  Ben  Davis.  The  trees 
were  planted  thirty-two  feet  apart  each  way. 

The  general  vigor  of  the  trees  was  good,  for  in  previous  years  they 
had  received  some  cultivation  and  pruning.  No  spraying,  however, 
had  ever  been  done  in  the  orchard ;  consequently  the  trees  had  never 
produced  anything  but  bulk  and  cider  apples.  The  fact  that  the  trees 
had  never  received  any  spray  assured  an  infection  of  scab  and  insects 
and  offered  good  conditions  for  carrying  on  these  experiments. 

TREATMENT 

The  plats  in  the  orchard  were  treated  as  shown  in  the  accom- 
panying schedule: 


Plat 

Application 

Treatment 

A 

1:  April  27 

Lime  sulfur  arsenate  of  lead 

2:  May     10 

Bordeaux           "         "    " 

3:  May     29 

»                 »         »    » 

B 

1:   April   27 

Lime  sulfur  arsenate  of  lead 

2:  May       9 

»         »                »           y>» 

3:  May     29 

Bordeaux            "         "    " 

C 

1:   April   27 

Lime  sulfur  arsenate  of  lead 

2:   May     10 

Bordeaux 

3:  May     29 

Lime  sulfur       " 

D 

1:  April  27 

Lime  sulfur  arsenate  of  lead 

2:  May       9 

}  }       »             >  t        »    }  > 

3:  May     29 

>  >       >  >             >  >        »    » 

E 

1:   April.  27 

Bordeaux  arsenate  of  lead 

2:  May       9 

Lime  sulfur    "        "    " 

3:  May     29 

Bordeaux 

F 

1:   April   27 

Bordeaux  arsenate  of  lead 

2:  May     10 

»                >  >        }  )    » 

3:  May     29 

»                »        »    a 

1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


173 


Plat 

Appli  cation                                                  Treatment 

G 

1:   April   27 

Bordeaux  arsenate  of  lead 

2:  May     10 

Lime  sulfur    "        "    " 

3:  May     29 

»        )  )        »        »    » 

H 

1:  April  27 

Bordeaux  arsenate  of  lead 

2:  May     10 

>  !                            )  }               »       » 

3:  May     29 

Lime  sulfur    "        "    " 

I 

1:  April  30 

Copper  ferroeyanide  arsenate  of  lead,  1-1-4—100 

2:  May     12 

"    »      i_i_4_ioo 

3:  May     31 

»    »       1_1_4_100 

J 

1:  April   30 

Copper  ferrocyanide  arsenate  of  lead,  l%-l%-4-100 

2:  May     12 

"    "      1V2-1V2-4-100 

3:  May     31 

l%-l%-±-100 

K 

1:  April  30 

Copper  ferrocyanide  arsenate  of  lead,  2-2^4-100 

2:  May     12 

"    »      2-2-4-100 

3:  May     31 

"                  "                   "          "     "       2-2-4-100 

L 

1:   April   30 

Copper  ferroeyanide  alone,  1-1-100 

2:  May     11 

"        1-1-100 

3:  May     31 

"         1-1-100 

M 

1:  April   30 

Copper  ferroeyanide  alone,  1%-1%-100 

2:  May     11 

"        1%-1%-100 

3:  May     31 

1%.-1%-100 

N 

1:   April   30 

Copper  ferrocyanide  alone,  2-2-100 

2:  May     11 

'  '        2-2-100 

3:  May     31 

"                                 "        2-2-100 

O 

1:   April   27 

Lime  sulfur  alone 

2:  May     10 

»         »        » 

3:  May     31 

y  >         >  >        » 

P 

1:   April   27 

Arsenate  of  lead  alone,  4—100 

2:  May     10 

»         >'       4-100 

3:  May     31 

"          "      "         "       4-100 

Q 

1:   April   30 

Lime  sulfur  (1  in  36)  arsenate  of  lead 

2:   May       9 

)t         »         1   '  '  36           "          "      " 

3:  May     31 

»         >  >         1   "  36           "          "      " 

R 

1:  April   30 

Lime  sulfur   (1  in  24)   arsenate  of  lead 

2:  May       9 

»         »         1   '  '  24           "          "      " 

3:  May     31 

>  j          j  j         1   "  24           "          "      " 

S 

1:   April   30 

Lime  sulfur  (1  in  14)  arsenate  of  lead 

2:  May       9 

»         }>         1"14          "         "     " 

3:  May     31 

»          »  •       1  '  "  14           "          "      " 

Check 

none 

No  treatment 

In  laying  out  these  experiments  the  trees  were  divided  into  twenty- 
one  plats  of  eight  or  nine  trees  each,  and  a  check  or  unsprayed  row 
was  left  thru  the  entire  length  of  the  orchard.  These  plats  were 
grouped,  and  each  group  was  sprayed  as  nearly  under  the  same  con- 
ditions as  possible,  so  that  the  plats  in  each  group  should  be  strictly 
comparable. 

APPARATUS  AND  PREPARATION  OF  MATERIALS 

In  all  cases  where  Bordeaux  was  used  in  these  treatments  it  was 
made  according  to  the  standard  formula:  8  pounds  copper  sulfate 
and  8  pounds  lime  to  100  gallons  of  water.  The  lime  sulfur  was  made 
according  to  the  Illinois  formula:  50  pounds  lime  and  100  pounds 
sulfur,  boiled  together  in  66  gallons  of  water  until  all  the  sulfur  was 


174 


BULLETIN  No.  185 


[February, 


(f))Ben  Davis       (WBen  Davis        Bother  varieties 
^  W  Check  \J 

CHART  11. — PLAN  OF  PLATS  IN  ORCHARD  OF  MR.  F.  TURNBULL,  GRIGGSVILLE,  1912 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  175 

in  solution.  Unless  otherwise  stated  this  was  used  at  the  rate  of  1 
gallon  in  18  gallons  of  water  (approximately  8  pounds  of  sulfur  in 
100  gallons).  Copper  ferrocyanide  was  made  from  equal  amounts  of 
copper  sulfate  and  potassium  ferrocyanide,  diluted  in  equal  parts  of 
water,  and  then  run  together;  Grasselli  arsenate  of  lead  paste  was 
used  at  the  rate  of  4  pounds  to  100  gallons  of  spray. 

SPRAY  DATES 

All  sprays  were  applied  with  a  Friend  power  spray  outfit  at  150 
to  175  pounds  pressure.  Double  Vermorel  nozzles  were  used.  Three 
applications  were  made :  the  first  in  the  cluster-bud  stage ;  the  second 
at  the  dropping  of  the  petals ;  and  the  third  about  three  weeks  later. 

CHARACTER  OP  RECORDS  AND   METHOD   OP  MAKING 

During  the  season  records  were  kept  including  the  appearance  of 
the  foliage  thruout  the  season  in  regard  to  fungi,  insects,  spray  injury, 
and  vigor.  Dropped  apples  were  counted  and  examined  for  various 
injuries.  At  picking  time  four  representative  trees  from  each  sprayed 
plat  and  seven  from  the  unsprayed  row  were  selected  and  as  many 
of  the  apples  as  the  sorting  table  would  conveniently  hold  were  taken 
from  all  parts  of  each  tree ;  from  these,  200  representative  apples  were 
selected  and  examined  carefully.  The  results  from  the  four  trees  in 
each  plat  were  averaged,  and  the  average  taken  to  indicate  the  value 
of  the  treatment.  The  fruit  from  the  seven  unsprayed  trees  was  re- 
corded in  like  manner.  All  the  apples  from  each  tree  in  each  plat,  and 
from  each  tree  in  the  check  row,  were  counted,  weighed,  and  graded 
according  to  the  standard  adopted  by  the  Illinois  State  Horticultural 
Society.1 

WEATHER   CONDITIONS 

The  weather  during  the  late  spring  and  early  summer  was  very 
wet  and  rather  cool.  However,  at  no  time  after  the  trees  started 
their  growth  did  the  temperature  drop  below  40  degrees.  The  trees 
were  in  full  bloom  May  4,  and  a  heavy  rain  occurred  during  that 
night. 

RELATIVE  VALUE  OF  LIME  SULFUR  AND  BORDEAUX 

As  a  further  test  of  the  relative  value  of  lime  sulfur  and  Bordeaux 
in  this  section  of  the  state,  plats  were  again  sprayed  with  these  mate- 
rials as  shown  in  Table  47. 

EFFECT   ON   FOLIAGE 

About  May  15  the  slightly  elevated  green  spots  of  apple  scab  be- 
gan to  appear  on  the  foliage  of  the  unsprayed  trees.  On  examining 
the  foliage  on  Plats  D  and  F,  practically  no  scab  was  found;  this 

'See  footnote,  page  60. 


176  BULLETIN  No.  185  [February, 

was  true  for  the  rest  of  the  season,  indicating  that  lime  sulfur  and 
Bordeaux  were  equally  effective  in  their  control.  This  was  not  true, 
however,  in  regard  to  leaf  spot  (Sphaeropsis  malorum),  which  was 
more  in  evidence  on  the  foliage  of  the  trees  sprayed  with  Bordeaux 
than  on  the  trees  sprayed  with  lime  sulfur.  The  unsprayed  trees 
showed  a  great  deal  of  leaf  spot  due  to  this  fungus.  A  little  Bor- 
deaux injury  appeared  on  the  foliage  in  the  form  of  small  brown 
spots  about  four  days  after  the  second  application.  The  trees  sprayed 
with  Bordeaux  suffered  from  an.  epidemic  of  yellow-leaf  June  25, 
and  a  second  outbreak  occurred  August  10,  reducing  the  amount  of 
foliage  materially.  Thruout  a  considerable  part  of  the  season  these 
trees  were  easily  recognized  by  the  scanty  development  of  their  leaves. 
The  trees  sprayed  with  lime  sulfur,  on  the  other  hand,  retained  a 
dense,  deep  green  foliage,  and  showed  practically  no  spray  injury  at 
any  time  during  the  season. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined  on 
October  14  and  15,  with  the  results  presented  in  Table  47. 

Scab. — The  data  presented  show  that  Bordeaux  was  slightly  super- 
ior to  lime  sulfur  in  the  control  of  apple  scab,  but  the  difference,  .15 
percent  serious  and  4.25  percent  slight  scab,  is  so  slight  that  the  two 
may  be  considered  to  have  been  equal  in  efficiency.  The  unsprayed 
row  showed  68.36  percent  serious  and  21  percent  slight  scab,  indicat- 
ing that  both  Bordeaux  and  lime  sulfur  were  very  effective  in  the 
control  of  this  disease.  Flyspeck  and  sooty  blotch  appeared  on  the 
fruit  of  the  unsprayed  trees  late  in  September,  but  the  attack,  as  the 
records  indicate,  was  not  very  serious  in  character.  All  diseases 
were  well  controlled  by  both  lime  sulfur  and  Bordeaux,  the  latter 
giving  slightly  better  results. 

Codling  Moth  and  Curculio. — The  arsenate  of  lead  in  both  sprays 
effectively  prevented  damage  from  codling  moth.  The  amount  of  in- 
jury done  by  the  plum  curculio  was  reduced  from  a  total  of  72.14 
percent  on  the  unsprayed  trees  to  12.12  percent  on  the  lime-sulfur 
plat  and  9.24  percent  on  the  Bordeaux  plat.  Nearly  all  of  the  cur- 
culio injury  recorded  from  these  sprayed  plats  was  in  the  form  of 
healed-over  egg  punctures  made  by  the  spring  generation  of  curculio. 
while  most  of  the  injury  on  the  unsprayed  trees  was  caused  by  the 
feeding  punctures  of  the  new  brood. 

Russet. — A  very  important  difference  between  the  effects  of  these 
sprays  upon  the  fruit  is  shown  in  the  russet  columns.  There  was 
23.4  percent  serious  and  53.5  percent  slight  russet  on  the  trees  sprayed 
with  Bordeaux,  as  compared  with  1  percent  and  12.75  percent  injury 
on  the  trees  sprayed  with  lime  sulfur.  Reference  to  the  amount  of 
russet  on  the  unsprayed  trees  will  show  that  4.07  percent  serious  and 
11.2  percent  slight  russet  may  have  been  caused  by  something  other 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


177 


Percentage  of  picked  apples  affected  by 

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178  BULLETIN  No.  185  [February, 

than  the  sprays.  As  these  amounts  were  present  on  the  unsprayed 
trees,  the  indications  are  that  the  russet  on  the  plat  sprayed  with  lime 
sulfur  was  not  caused  by  the  spray.  By  the  same  reasoning,  however, 
it  would  appear  that  19.33  percent  of  the  serious  russet  and  42.3  per 
cent  of  the  slight  russet,  in  Plat  F,  can  be  attributed  to  Bordeaux. 

On  examining  these  results  for  the  percentage  of  the  different 
grades  of  fruits,  we  note  that  the  lime-sulfur  plat  had  69  percent  No. 
1's,  27  percent  No.  2's,  and  4  percent  culls,  as  compared  with  the 
Bordeaux  plat  with  56,  33,  and  11  percent,  respectively,  of  the  same 
grades.  The  differences  were  due  to  Bordeaux  russet.  There  was  a 
marked  contrast  between  the  lime-sulfur  and  the  Bordeaux-sprayed 
apples.  Those  sprayed  with  lime  sulfur  were  large  and  smooth,  with 
a  waxy  finish  and  very  high  color,  while  those  sprayed  with  Bordeaux 
were  smaller,  often  badly  russeted  and  distorted,  poorly  colored,  and 
lacking  in  finish. 

VALUE  OF  INTERCHANGING  LIME  SULFUR  AND  BORDEAUX  AS 
SUMMER  SPRAYS 

The  results  just  discussed  show  Bordeaux  and  lime  sulfur  to  be 
almost  equally  efficient  as  sprays  for  scab,  flyspeck,  and  sooty  blotch, 
but  they  indicate  that  Bordeaux  is  objectionable  because  of  its  in- 
jurious effect  on  the  fruit  and  foliage.  Results  in  previous  years  in- 
dicated that  russeting  accompanies  Bordeaux  sprays  applied  soon 
after  the  setting  of  the  fruit.  It  has  been  suggested,  therefore,  that 
lime  sulfur  might  be  substituted  for  Bordeaux  at  this  critical  time, 
retaining  Bordeaux  for  other  sprays.  In  order  to  determine  the  ef- 
fects of  such  a  substitution,  plats  were  treated  as  shown  in  Table  48. 

EFFECT  ON  FOLIAGE 

All  the  sprays  controlled  apple  scab  effectively  on  the  foliage. 
There  were,  however,  differences  in  the  appearance  of  the  foliage  as 
regards  spray  injury.  A  few  days  after  the  second  application,  Bor- 
deaux injury  made  its  appearance  on  Plats  A,  C,  and  H.  The  cool 
wet  weather  at  this  time  may  have  been  a  factor  in  causing  the  injury. 
The  foliage  of  Plats  B,  E,  and  G  was  in  good  condition.  On  Juno 
25,  about  three  weeks  after  the  third  application,  Bordeaux  injury  in 
the  form  of  yellow  leaves  appeared  on  Plats  A,  B,  and  E,  and  on 
August  10  a  second  outbreak  appeared.  This  so  greatly  reduced  tho 
amount  of  foliage  on  Plat  E  that  the  trees  resembled  those  sprayed 
at  all  applications  with  Bordeaux.  Plat  E  did  not  recover  from  this 
attack  and  retained  only  a  scanty  supply  of  leaves  for  the  rest  of  the 
season.  Plat  A  was  affected  in  much  the  same  manner.  Plats  B,  C, 
G,  and  H  recovered  from  the  injury  and  took  on  a  good  foliage  for 
the  remainder  of  the  season.  It  was  evident  that  the  fewer  the  sprays 
of  Bordeaux  the  plats  received,  the  less  was  the  resulting  foliage  in- 
jury. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  179 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  14  to  16.  The  data  as  presented  in  Table  48  show  that  the 
treatments  given  Plats  E,  G,  and  H  were  the  most  effective  in  con- 
trolling scab,  Plats  A,  B,  and  C  having  the  greatest  amount.  The 
former  three,  as  may  be  noted,  were  sprayed  the  first  time  with  Bor- 
deaux, and  the  latter  three  with  lime  sulfur.  All  the  plats  in  this 
series  were  sprayed  first  on  April  27,  and  on  the  next  day  four  inches 
of  cold-beating  rain  fell.  It  is  probable  that  less  of  the  Bordeaux  was 
washed  off  than  of  the  lime  sulfur,  the  former  being  more  adhesive, 
and  that  the  superior  efficiency  of  Bordeaux  in  controlling  scab  may 
have  been  due  to  its  greater  adhesiveness. 

A  small  amount  of  flyspeck  or  sooty  blotch  was  found  on  Plats 
A.  B,  and  C.  On  all  plats  codling-moth  and  curculio  injury  were 
reduced  materially. 

The  largest  important  differences  occur  in  the  amount  of  russet 
found  on  the  different  plats.  It  is  a  question  as  to  how  long  aftev 
the  petals  have  fallen  applications  of  Bordeaux  will  cause  russet.1  An 
examination  of  the  results  for  Plat  G,  where  Bordeaux  was  used  only 
at  the  first  or  cluster-bud  spray,  shows  17.87  percent  serious  russet  and 
37.12  percent  slight  russet.  Plat  C,  where  Bordeaux  was  used  only  at 
the  time  of  the  second  application,  immediately  after  the  bloom,  showed 
3.89  percent  serious  russet  and  34.9  percent  slight.  Plat  B,  where  Bor- 
deaux was  used  for  only  the  third  application,  three  weeks  after  the  fall 
of  the  bloom,  showed  4.7  percent  serious  russet  and  44.3  slight.  It  is  to 
be  observed,  however,  that  on  the  unsprayed  row  4.07  percent  serious 
russet  appeared  and  11.2  percent  slight.  The  true  effects  of  the  sprays 
are  determined,  therefore,  by  subtracting  the  amounts  of  russet  on 
the  unsprayed  trees  from  those  on  the  sprayed  trees.  In  doing  this 
for  Plat  G,  it  was  found  that  Bordeaux  applied  at  the  cluster-bud 
stage  actually  caused  13.8  percent  serious  russet  and  25.92  percent 
slight;  that  Plat  C,  sprayed  with  Bordeaux  immediately  after  the 
bloom,  showed  23.7  slight  russet ;  and  that  Plat  B,  sprayed  with  Bor- 
deaux three  weeks  after  the  bloom,  showed  33.1  percent  slight  russet. 
From  these  results  it  may  be  concluded  that  where  Bordeaux  was  ap- 
plied just  before  the  bloom,  just  after  the  fall  of  the  petals,  or  within 
three  weeks  after  their  fall,  russet  was  the  most  important  factor  in 
reducing  the  percentage  of  No.  1  apples.  The  more  seldom  Bordeaux 
was  used  and  the  more  often  lime  sulfur  was  used,  the  better  the 
color,  finish,  and  smoothness  of  the  fruit. 

FUNGICIDAL  AND  INSECTICIDAL  VALUE  OF  VARIOUS  STRENGTHS 
OF  COPPER  FERROCYANIDE 

To  test  the  fungicidal  and  insecticidal  value  of  copper  ferrocyan- 
ide  at  different  strengths,  plats  were  treated  as  shown  in  Table  49. 
'U.  P.  Hedrick,  N.  Y.   (Geneva)  Agr.  Exp.  Sta.  Bui.  287,  p.  163. 


180 


BULLETIN  No.  185 


[February-, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  181 

EFFECT  ON  FOLIAGE 

Apple  scab  appeared  on  the  foliage  of  all  the  sprayed  plats  about 
the  time  it  appeared  on  the  unsprayed  row,  and  caused  severe  damago 
thruout  the 'season.  On  Plats  I,  J,  and  K,  which  were  sprayed  with 
copper  ferrocyanide  arsenate  of  lead,  the  amounts  of  scab,  leaf  spot, 
and  insect  work  on  the  foliage  were  not  as  severe  as  on  Plats  L,  M, 
and  N,  where  the  arsenate  of  lead  was  omitted.  This  indicates  that 
the  arsenate  of  lead  not  only  possessed  insecticidal  but  also  some  fun- 
gicidal  value.  There  was  a  striking  difference  between  the  retention 
of  the  foliage  of  Plats  I  and  L,  due  seemingly  to  the  use  or  omission 
of  arsenate  of  lead.  From  these  results  it  appeared  that  arsenate  of 
lead  possessed  considerable  value,  directly  or  indirectly,  as  a  fungi- 
cide. Toward  the  end  of  the  season,  Plats  L,  M,  and  N  were  com- 
pletely defoliated,  and  could  not  be  distinguished  from  the  unsprayed 
trees.  Copper  ferrocyanide  alone,  in  the  three  strengths  tested  and 
under  the  conditions  which  prevailed  in  the  experimental  work  at 
Griggsville  in  1912,  had  practically  110  value  as  a  fungicide  or  insecti- 
cide on  apple  foliage.  This  spray  lacked  adhesiveness  and  was  easily 
washed  off  by  rains.  The  addition  of  arsenate  of  lead  may  have  in- 
creased its  adhesiveness,  a  possibility  that  may  explain  to  some  extent 
the  better  control  of  fungi  in  Plats  I,  J,  and  K.  Some  foliage  injury 
in  the  form  of  brown  spots  appeared  on  all  plats  about  June  25.  This 
injury  was  visible  during  the  remainder  of  the  season. 

EFFECT   ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  16  to  18.  From  the  results  presented  in  Table  49  we  learn 
that  copper  ferrocyanide  when  used  alone  at  these  three  strengths  has 
very  little  value,  if  any,  as  a  spray  for  scab.  These  sprays,  however, 
considerably  reduced  flyspeck  and  sooty  blotch,  altho  they  had  no  effect 
on  codling  moth  and  but  little  on  curculio.  In  Plats  I,  J,  and  K,  where 
arsenate  of  lead  was  used,  it  will  be  noted  that  the  sprays  reduced 
scab,  flyspeck,  and  sooty  blotch  considerably.  This  reduction  was 
probably  due  in  some  manner  to  the  arsenate  of  lead.  The  arsenate 
of  lead  of  the  sprays  also  controlled  codling  moth  and,  to  some  extent, 
curculio.  The  percentage  of  No.  1  fruit  on  Plats  L,  M,  and  N,  where  no 
arsenate  of  lead  was  used,  hardly  more  than  equaled  that  on  the  un- 
sprayed row,  while  for  Plats  I,  J,  and  K,  where  arsenate  of  lead  was 
used  in  combination  with  copper  ferrocyanide,  the  percentage  of  No. 
1  fruit  was  strikingly  higher.  The  percentage  of  No.  2's  and  culls 
was  less  where  arsenate  of  lead  was  used.  The  fruit  from  Plats  L, 
M,  and  N  resembled  that  from  the  unsprayed  row,  for  it  was  small, 
scabby,  badly  damaged  by  insects,  and  lacked  color.  The  apples  be- 
gan dropping  prematurely,  as  did  the  foliage,  because  of  serious  fun- 
gous and  insect  injuries.  The  fruit  from  Plats  I,  J,  and  K  took  on  an 


182 


BULLETIN  No.  185 


[February, 


TABLE  49.—  EFFECTS  OF  VARIOUS  DILUTIONS  OF  COPPER  FERROCTANIDE  WITH  AND  WITHOUT  ARSENATE  OF  LEAD,  IN  THE  EXPERIMENTS 
AT  GRIGGSVILLE,  1912 

Percentage  of  picked  apples  affected  by 

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11)16]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  183 

excellent  color,  tho  it  was  small  and  scabby.     The  arsenate  of  lead 
had  a  stimulating  effect  on  color. 

It  must  be  concluded,  therefore,  that  under  the  conditions  which 
prevailed  in  the  Griggsville  experiments  in  1912,  copper  ferrocyanide, 
as  a  summer  spray,  was  practically  useless. 

EFFECT  OF  THE  ADDITION  OF  ARSENATE  OF  LEAD  TO  LIME  SULFUR 

The  addition  of  arsenate  of  lead  to  lime-sulfur  solution  causes  a 
chemical  reaction  which  changes  the  composition  of  a  small  amount 
of  each.1  It  is  also  known  that  the  addition  of  arsenate  of  lead  to 
lime  sulfur  affects  the  fungicidal  value  of  that  spray.1  To  determine 
the  effect  of  the  addition  of  arsenate  of  lead  to  lime  sulfur  under  the 
conditions  existing  in  this  part  of  the  state,  three  plats  were  treated 
as  shown  in  Table  50. 

EFFECT  ON  FOLIAGE 

On  the  foliage  of  Plat  0,  which  was  sprayed  with  lime  sulfur  alone, 
there  was  a  slight  infection  of  scab,  but  on  the  foliage  of  Plat  P, 
sprayed  with  arsenate  of  lead  alone,  there  was  considerable  infection, 
tho  less  severe  than  on  the  check  row.  The  foliage  of  Plat  D,  sprayed 
with  lime  sulfur  arsenate  of  lead,  showed  practically  no  scab.  There 
was  some  leaf  spot  on  Plats  0  and  P,  but  Plat  D  showed  almost  no 
infection  with  this  fungus.  The  addition  of  arsenate  of  lead  to  lime 
sulfur  apparently  increased  the  fungicidal  value  of  that  spray. 

There  was  some  insect  work  on  the  foliage  of  Plat  0  due  to  the 
absence  of  arsenate  of  lead,  and  the  leaves  were  not  so  deeply  colored 
as  those  on  the  trees  of  Plats  P  or  D.  Plat  P  showed  a  little  foliage 
injury  in  the  form  of  brown  edges  and  tips,  but  the  amount  was  al- 
most negligible. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  11  to  12.  The  results  as  presented  in  Table  50  show  that 
lime  sulfur  when  used  alone  controlled  scab  very  effectively  on  the 
fruit.  Of  the  apples  sprayed  with  arsenate  of  lead  alone,  37.5  per- 
cent were  infected  with  serious  scab,  and  31.5  percent  with  slight  scab. 
Arsenate  of  lead,  however,  increased  the  fungicidal  value  of  lime 
sulfur,  for  in  comparing  the  results  for  scab  on  Plat  0,  sprayed  with 
lime  sulfur  alone,  and  Plat  D,  sprayed  with  lime  sulfur  and  arsenate 
of  lead,  we  note  a  small  difference  in  favor  of  the  latter  plat.  There 
was  a  little  more  flyspeck  and  sooty  blotch  on  Plat  O  than  on  Plat  P, 
owing  possibly  to  the  fact  that  Plat  0  was  located  in  a  slightly  lower 
part  of  the  orchard. 

Arsenate  of  lead  controlled  codling  moth  perfectly,  while. lime  sul- 
fur had  no  effect  upon  it.  In  curculio  injury  a  decided  reduction 
may  be  noted  in  all  sprayed  plats  as  compared  with  the  check  row. 

1E.  Wallace,  N.  Y.  (Cornell)  Agr.  Exp.  Sta.  Bui.  289,  p.  146. 


184 


BULLETIN  No.  185 


Percentage  of  picked  apples  affected  by 

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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  185 

The  reduced  amount  of  injury  on  Plat  P  was  due  to  the  arsenate  of 
lead.  Just  why  the  amount  of  cureulio  injury  on  Plat  0  was  re- 
duced in  comparison  to  what  appeared  on  the  unsprayed  row  would 
be  difficult  to  explain,  and  yet  it  is  important.  Apparently  the  lime 
sulfur  acted  as  a  repellent. 

Scab  reduced  the  percentage  of  No.  1  apples  in  Plat  P,  sprayed 
with  arsenate  of  lead  alone,  in  comparison  with  Plat  0,  where  lime 
sulfur  alone  was  used.  The  fruit  from  Plat  P  had  a  better  color  and 
smoother  finish  than  that  from  Plat  0.  Arsenate  of  lead  again  showed 
a  stimulating  effect  on  color  and  finish. 

RELATIVE  VALUES  OF  VARIOUS  STRENGTHS  OF  LIME  SULFUR 

In  the  preceding  experiments  in  which  lime  sulfur  was  used,  the 
amount  of  sulfur  in  solution  was  approximately  8  pounds  to  each  100 
gallons  of  spray.  To  determine  the  efficiency  of  various  strengths  of 
homemade  lime  sulfur,  four  plats  were  treated  as  shown  in  Table  51. 

EFFECT  ON   FOLIAGE 

All  the  sprays  held  both  scab  and  leaf  spot  in  check;  there  Avas 
practically  no  scab  during  the  entire  season  on  all  four  plats.  The 
foliage  was  similar  in  appearance, — very  dense,  and  dark  green  in 
color.  The  different  sprays  had  a  decidedly  stimulating  effect  on  the 
size  and  smoothness  of  the  leaves,  and  caused  almost  no  injury.  The 
foliage  of  the  sprayed  plats  remained  on  the  trees  until  after  No- 
vember 7,  while  that  of  the  unsprayed  row  was  completely  gone  by 
October  10.  The  retention  of  this  dense  green  foliage  so  late  in  the  sea- 
son seemed  to  increase  the  size  and  vigor  of  the  fruit  buds,  as  the  differ- 
ence in  size  between  the  buds  on  these  plats  and  those  on  the  plats  which 
suffered  considerable  foliage  injury  from  spray  was  very  apparent. 

EFFECT  ON  FRUIT 

The  apples  from  these  plats  were  picked,  sorted,  and  examined 
October  9  to  11.  The  results  as  presented  in  Table  51  show  that  the 
spray  given  Plat  S  controlled  scab  on  the  fruit  almost  perfectly,  there 
being  but  .12  percent  severe  scab  and  1  percent  slight  scab.  Plats  Q, 
R,  and  D  show  about  the  same  percentages  of  scab,  only  slightly  more 
than  Plat  S.  Flyspeck  was  controlled  on  all  plats  except  Plat  D,  where 
the  injury  was  negligible.  All  sprays  controlled  sooty  blotch  with  the 
exception  of  those  used  on  Plats  D  and  R,  where  the  infection  was 
very  slight.  Codling-moth  control  was  almost  perfect  on  all  plats. 
Injury  from  cureulio  was  reduced  materially  by  all  the  sprays.  All 
plats  produced  a  high  percentage  of  No.  1  fruit,  Plat  S  the  highest. 

The  fruit  from  all  these  plats  took  on  a  very  high  color  and  a 
smooth  waxy  finish  and  was  of  good  size.  The  apples  en  Plat  S  seemed 
to  have  a  deeper  and  better  distributed  color  than  those  on  the  other 


186  BULLETIN  No.  185  [February, 

plats.  On  all  plats  the  stimulating  effects  of  lime  sulfur  and  arsenate 
of  lead  on  the  color  and  smoothness  of  the  fruit  was  further  demon- 
strated. These  plats  were  the  best  of  any  in  the  orchard  on  account  of 
the  freedom  of  the  fruit  from  fungi  and  insects,  the  large  size,  high  col- 
or, and  smoothness  of  the  fruit,  and  the  heavy,  dense  green  foliage. 

SUMMARY  OF  EESULTS  AT  GRIGGSVILLE,  1912 

1.  Homemade  lime  sulfur  containing  8  pounds  of  sulfur  and  4 
pounds  of  arsenate  of  lead  to  100  gallons  proved  equal  to  Bordeaux 
arsenate  of  lead,  8-8-4-100,  as  a  spray  for  apple  scab,  and  the  two 
sprays  were  practically  equal  in  their  control  of  flyspeck  and  sooty 
blotch. 

2.  Three  applications  of  Bordeaux  arsenate  of  lead  caused  severe 
injury  to  foliage  and  badly  russeted  the  fruit,  while  lime  sulfur  ar- 
senate of  lead  did  not  injure  the  foliage  seriously  nor  russet  the  fruit. 

3.  Lime  sulfur  arsenate  of  lead  had  an  invigorating  effect  on  the 
foliage  and  a  stimulating  effect  on  the  color  and  size  of  the  fruit,  be- 
sides giving  it  a  very  waxy  finish. 

4.  Some  russeting  of  the  fruit  resulted  from  each  of  the  three 
applications  of  Bordeaux. 

5.  Bordeaux  injury  to  fruit  and  foliage  developed  under  cool,  wet 
conditions. 

6.  The  severe  foliage  injury  caused  by  Bordeaux  had  a  detri- 
mental effect  on  the  development  of  the  next-year's  fruit  buds.    The 
buds  on  lime-sulfur  trees  were  large,  plump,  and  well  developed,  while 
the  buds  on  the  trees  sprayed  with  Bordeaux  were  smaller  and  ap- 
parently not  so  well  developed. 

7.  Copper  ferrocyanide  proved  practically  useless  as  a  fungicide 
or  insecticide. 

8.  Lime  sulfur  arsenate  of  lead  was  slightly  more  effective  in 
controlling  scab,  flyspeck,  and  sooty  blotch  than  lime  sulfur  alone. 
The  arsenate  of  lead  may  have  increased  the  adhesiveness  of  the  lime 
sulfur. 

9.  Fruit  sprayed  with  arsenate  of  lead  alone  had  a  higher  color 
than  that  sprayed  with  lime  sulfur  alone,  indicating  that  arsenate  of 
lead  stimulates  color. 

10.  Arsenate  of  lead  alone  had  some  fungicidal  value  and  caused 
but  a  negligible  amount  of  foliage  injury. 

11.  Various  strengths  of  homemade  lime  sulfur  containing  4,  6, 
8,  and  10  pounds  of  sulfur  together  with  4  pounds  of  arsenate  of  lead 
to  100  gallons,  controlled  scab,  flyspeck,  and  sooty  blotch  effectively, 
and  gave  excellent  foliage  and  highly  colored,  large,  smooth  fruit. 
The  10-pound  strength  (10-100)   was  the  most  efficient,  controlling 
scab  almost  perfectly;  less  than  2  percent  of  the  fruit  was  infected 
with  scab ;  and  the  color  of  the  fruit  was  deeper  and  better  distributed. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  187 

GENERAL  SUMMARY 

BY  B.  S.  PICKETT 

In  this  summary  the  writer  has  attempted  to  answer  the  questions 
presented  in  the  introduction  (pages  50  and  51),  to  point  out  certain 
facts  which  are  not  specifically  mentioned  in  the  questions  referred 
to,  and  to  make  recommendations  for  the  general  spraying  of  apple 
orchards  in  Illinois.  Where  the  material  would  permit,  results  from 
the  various  experiments  are  tabulated  for  convenient,  reference.  The 
data  answering  several  of  the  questions,  however,  could  not  be  tabu- 
lated advantageously,  and  such  results  are  presented  in  the  form  of 
brief  summaries  or  statements  from  the  annual  reports  of  the  individ- 
ual experiments. 

SUMMARY  OF  DATA 

1.  What  is  the  general  effectiveness  of  applications  of  standard 
spray  mixtures,  including  Bordeaux,  lime  sulfur,  and  arsenate  'of  lead 
in  the  control  of  fungi  and  insects  on  the  apple? 

No  fact  stands  out  more  distinctly  in  a  study  of  the  data  presented, 
in  the  reports  included  in  this  bulletin  than  the  general  effectiveness 
of  spraying  over  no  spraying.  Even  under  the  most  unfavorable  cir- 
cumstances, some  degree  of  benefit  has  resulted  from  the  application 
of  all  of  the  standard  sprays  in  every  series  of  experiments  and  in 
every  year  of  the  experimentation.  Year  after  year  the  sprayed  plats 
have  been  conspicuous  by  their  more  healthy  and  vigorous  foliage  and 
by  the  freedom  of  their  fruit  from  insects  and  diseases.  Of  necessity 
the  benefits  from  spraying  have  varied  more  or  less  from  season  to 
season.  In  1911  both  diseases  and  insects  were  conspicuous  by  their 
comparative  absence.  Even  unsprayed  orchards  produced  consider- 
able fruit  of  good  quality.  Under  such  conditions  the  best  possible 
effects  of  sprays  are  not  fully  demonstrated.  Nevertheless,  even  in 
1911,  spraying  proved  its  superiority  over  failure  to  spray  in  every 
case  experimented  upon. 

Tables  52  and  53  present  the  general  results  of  four  years'  experi- 
mentation in  an  attempt  to  answer  the  above  question.  Every  result 
thruout  the  reports  previously  presented  which  bears  directly  upon 
this  subject  has  been  included  in  these  tabulations.  . 

It  will  be  seen  from  Table  52  that  the  smallest  control  exercised 
over  apple  scab  as  a  result  of  spraying  at  least  three  times 
with  Bordeaux  or  Bordeaux  in  combination  with  arsenate  of  lead 
amounts  to  67  percent,  and  that  the  largest  control  amounts  to  98 
percent.  In  six  experiments  out  of  ten,  90  percent  or  over  of  all  the 
scab  which  might  have  appeared  in  the  sprayed  plats  was  prevented 
as  a  result  of  spraying  with  Bordeaux  or  Bordeaux  in  combination 
with  arsenate  of  lead. 


188 


BULLETIN  No.  185 


[February, 


TABLE   52. — GENERAL   EFFECTS   OF  THE    STANDARD   FUNGICIDES,  BORDEAUX  AND 

LIME  SULFUR 


Fungicide 

Year 

Place 

Experi- 
menter 

Table 

Percentage  of 
fruit    saved 
from     scab 
by  spray 

1  Percentage 
scab       con 
trolled      as 
compared 
with  checks 

Bordeaux 

'09 

Griggsville 

L.E.F. 

26 

47  to  56 

75  to    90 

Bordeaux 

'11 

Neoga 

O.S.W. 

6 

51  to  61 

67  to    80 

Bordeaux 

'11 

Neoga 

O.S.W. 

7 

67 

79 

Bordeaux 

'11 

Centralia 

L.E.F. 

28 

37  to  43 

84  to    98 

Bordeaux 

'11 

Griggsville 

A.J.G. 

41 

12 

98 

Bordeaux 

'12 

Neoga 

O.S.W. 

14 

72  to  87 

73  to    88 

Bordeaux 

'12 

Flora 

W.A.K. 

21 

14 

93 

Bordeaux 

'12 

Anna 

L.E.F. 

30 

33  to  34 

87  to    90 

Bordeaux 

'12 

Anna 

L.E.F. 

31 

57  to  71 

70  to    87 

Bordeaux 

'12 

Griggsville 

A.J.G. 

47 

66 

97 

Lime  sulfur 

'09 

Griggsville 

L.E.F. 

24 

17  to  56 

19  to    60 

Lime  sulfur 

-'10 

Neoga 

O.S.W. 

1 

6  to  85 

6  to    85 

Lime  sulfur 

'11 

Neoga 

O.S.W. 

6 

25  to  48 

33  to    63 

Lime  sulfur 

'11 

Neoga 

O.S.W. 

7 

55 

65 

Lime  sulfur 

'11 

Centralia 

L.E.F. 

28 

39  to  40 

89  to    91 

Lime  sulfur 

'11 

Griggsville 

A.J.G. 

41 

11 

91 

Lime  sulfur 

'11 

Griggsville 

A.J.G. 

46 

11  to  12 

91  to  100 

"Lime  sulfur 

'12 

Neoga 

O.S.W. 

14 

72  to  84 

72  to    84 

Lime  sulfur 

'12 

Neoga 

O.S.W. 

17 

41  to  52 

45  to    57 

Lime  sulfur 

'12 

Flora 

W.A.E. 

21 

15 

100 

Lime  sulfur 

'12 

Anna 

L.E.F. 

30 

26  to  34 

70  to    92 

Lime  sulfur 

'12 

Anna 

L.E.F. 

31 

51  to  65 

62  to    80 

Lime  sulfur 

'12 

Anna 

L.E.F.     . 

33 

39  to  56 

47  to    67 

Lime  sulfur 

'12 

Griggsville 

A.J.G. 

47 

70 

80 

Lime  sulfur 

'12 

Griggsville 

A.J.G. 

51 

78  to  88 

88  to    99 

Lime  sulfur  exercised  varying  degrees  of  control,  running  from 
as  low  as  6  percent  to  as  high  as  100  percent.  In  two  experiments 
out  of  fifteen,  100  percent  control  was  obtained.  In  six  experiments 
out  of  fifteen,  lime  sulfur  exercised  a  control  running  above  90  per- 
cent. In  five  cases  this  fungicide  prevented  less  than  50  percent  of 
the  possible  damage  from  apple  scab.  In  no  single  case,  however,  did 
it  fail  to  exercise  some  control  over  this  fungus,  and  in  those  experi- 
ments where  the  poorest  control  was  obtained,  certain  plats  showed 
an  effectiveness  varying  from  57  to  85  percent. 

In  the  twenty-nine  experiments  included  in  Table  53,  arsenate 
of  lead  did  not  fail  to  exercise  some  degree  of  control  over  codling 
moth  and  curculio  in  some  one  or  more  of  the  plats  included 
in  each  of  the  experiments.  In  four  cases,  however,  certain  sprayed 
plats  in  the  experiment  showed  more  injury  than  the  check  plats.  It 
will  be  observed,  however,  that  in  every  one  of  these  four  cases  the 
total  infestation  of  codling  moth  was  very  small,  the  largest  loss  due 
to  failure  of  the  spray  to  control  the  insect  amounting  to  3  percent 
of  the  entire  crop.  Under  the  circumstances  in  which  these  slightly 
inconsistent  results  appear,  the  inconsistency  must  be  attributed  to 
unequal  infection  rather  than  to  ineffectiveness  of  the  spray. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


189 


TABLE  53. — GENERAL  EFFECT  OF  THE  STANDARD  INSECTICIDE,  ARSENATE  OF  LEAD, 
ALONE  OR  IN  COMBINATION  WITH  VARIOUS  FUNGICIDES 


-*>  • 

•    bO'O 

"S  i* 

.    oj 

t» 
1 

'3  'o 

«w  ° 

<H    g 

|.5  £ 

°£a 

*"*  °  e 

'3  s 

?H      O 

i|f 

h 

8 

8 

£ 

0    S^ 

0>0 

ffl     tn 

0  °  n 

8 

,2 

•f 

r£5 

&UDC*H    2 

tUO5*-!           S 

So1*-! 

tUC1*-!    ® 

QJ 

M 

CO 

03            M 

03    °           o 

03 

C3   0   S   <n 

EH 

-1J           _ 

•fj      CI.M 

Pi 

pj    m    «.*\ 

«  _  "3  -a 

^            QJ           O 

£3       .    J^  %} 

M 

<P    ^.     ~JP 

§"0  "oS 

~              --         — 

<B    o    S    O> 

H 

8  8a 

g  |  g 

|Iil 

1 

PH 

£ 

£ 

£ 

'09,  Griggsville 

L.E.F. 

23 

5  to  12 

100 

21  to  35 

21  to    43 

;09,  Griggsville 

L.E.F. 

25 

14 

82 

No  control 

'09  Griggsville 

L.E.F. 

26 

17  to  19 

85  to    95 

25  to  30 

27  to    32 

'09  Griggsville 

L.E.F. 

27 

4  to  18 

33  to    95 

10  to  50 

10  to    64 

'10  Neoga 

O.S.W. 

1 

20  to  28 

71  to  100 

62  to  80 

62  to    85 

'10  Neoga 

O.S.W. 

4 

10  to  26 

36  to    93 

32  to  80 

32  to    80 

'10  Neoga 

O.S.W. 

5 

14  to  25 

oO  to  89 

46  to  81 

46  to    81 

'11  Neoga 

O.S.W. 

10 

-2  to     1 

-33  to    17 

-1  to     6 

-17  to  100 

'11  Neoga 

O.S.W. 

11 

5  to  16 

31  to  100 

-4  to  12 

-27  to    80 

'11  Centralia 

L.E.F. 

28 

7.8 

65 

0  to  14 

Oto    88 

'11  Griggsville 

A.J.G. 

41 

2  to     3 

42  to    74 

13  to  34 

24  to    61 

'11  Griggsville 

A.J.G. 

42 

-2  to     3 

-50  to    75 

11  to  24 

20  to    44 

'11  Griggsville 

A.J.G. 

43 

0  to  3.5 

Oto    90 

24  to  33 

44  to    61 

'11 

Griggsville 

A.J.G. 

44 

-1  to     3 

-25  to    75 

14  to  24 

26  to    44 

'11 

Griggsville 

A.J.G. 

45 

2  to     3 

50  to    75 

15  to  18 

28  to    34 

'11 

Griggsville 

A.J.G. 

46 

-3  to     3 

-75  to    75 

'12 

Anna 

L.E.F. 

30 

1  to  18 

2  to    36 

12  to  19 

32  to    51 

'12 

Anna 

L.E.F. 

31 

24  to  28 

86  to    93 

4  to  19 

11  to    51 

'12 

Anna 

L.E.F. 

35 

16  to  32 

34  to    63 

17  to  19 

46  to    51 

'12 

Anna 

L.E.F. 

36 

•16  to  27 

53  to    90 

-13  to     5 

-35  to    16 

'12 

Anna 

L.E.F. 

37 

2  to  18 

4  to    38 

-5  to  13 

-14  to    35 

'12 

Anna 

L.E.F. 

38 

18  to  24 

60  to    80 

8  to  14 

22  to    38 

'12 

Anna 

L.E.F. 

39 

2  to  24 

4  to    51 

5  to  19 

14  to    51 

'12 

Anna 

L.E.F. 

40 

18  to  27 

60  to    90 

4  to     8 

8  to    16 

'12 

Griggsville 

A.J.G. 

47 

3.43 

100 

60  to  63 

83  to    88 

'12 

Griggsville 

A.J.G. 

48 

3.2  to  3.4 

93  to  100 

53  to  64 

74  to    89 

'12 

Griggsville 

A.J.G 

49 

3.43 

100 

60  to  63 

83  to    88 

'12 

Griggsville 

A.J.G. 

50 

3.43 

100 

48  to  60 

67  to    83 

'12 

Griggsville 

A.J.G. 

51 

3.43 

100 

60  to  64 

83  to    89 

The  general  effectiveness  of  the  spray  will  be  seen  when  it  is  noted 
that  in  fifteen  experiments  of  the  twenty-nine  tabulated,  90  percent 
or  better  control  of  the  codling  moth  was  obtained  in  some  of  the  plats 
included. 

Curculio  was  less  thoroly  controlled  by  arsenate  of  lead  than  was 
codling  moth.  Nevertheless  in  only  six  of  the  experiments  were  there 
any  plats  which  failed  to  show  some  degree  of  prevention  of  injury 
by  reason  of  the  application  of  the  spray.  Eleven  experiments  out  of 
the  twenty-nine  included  some  plats  in  which  80  percent  or  more  of 
the  injury  was  prevented  by  the  application  of  the  spray. 

2.  What  are  the  relative  values  of  Bordeaux  and  lime  sulfur  as 
sprays  for  tJie  apple  ? 

Table  54  presents  a  summary  of  the  comparative  values  of  Bor- 
deaux and  lime  sulfur  in  the  various  experiments  during  1909-12. 


190 


BULLETIN  No.  185 


TABLE  54. — COMPARATIVE  EFFECTIVENESS  OF  BORDEAUX  AND  LIME  SULFUR  AS 
SUMMER  SPRAYS  FOR  APPLES 


Year 

Place 

Experimenter 

Page 

Lime  sulfur 
compared 
with 
Bordeaux 

As  regards 

'09 

Griggsville 

L.E.P. 

121-124 

Inferior 

Scab  on  fruit 

'10 

Neoga 

O.S.W. 

61-62 

Inferior 

Scab  on  foliage 

62 

Superior 

Vigor  and  abundance  of  foliage 

'10 

Centralia 

L.E.F. 

128 

Equal 

Scab  on  foliage 

128 

Superior 

Spray  injury  to  foliage 

'11 

Neoga 

O.S.W. 

75-87 

Inferior 

Scab  on  fruit 

75-77 

Inferior 

Color  of  fruit 

74 

Inferior 

Spray  injury  to  foliage 

'11 

Centralia 

L.E.F. 

138 

Superior 

Eusseting  of  fruit 

133-134, 

Superior 

Vigor  and  abundance  of  foliage. 

138 

spray  injury  to  foliage 

134-137 

Inferior 

Scab,  blotch,  and  sooty  blotch 

on  fruit 

'11 

Griggsville 

A.J.G. 

161-162 

Equal 

Scab  on  fruit 

161-162 

Inferior 

Flvspeck  and  sooty  blotch  on 

fruit 

161-163 

Superior 

Eusseting,  color,  and  finish  of 

fruit 

160-161 

Equal 

Scab  on  foliage 

160-161 

Superior 

Vigor  and  abundance  of  foliage 

'12 

Neoga 

O.S.W. 

94 

Inferior 

Scab  on  fruit 

94 

Inferior 

Amount  of  surface  colored 

94 

Superior 

Finish  of  fruit 

94 

Equal 

Yield  of  No.  1  apples 

92 

Inferior 

Scab  on  foliage 

'12 

Flora 

W.A.E. 

111 

Equal 

Scab  on  fruit 

116 

Superior 

Spray  injury  to  foliage 

117 

Superior 

Eusseting  of  fruit 

111 

Inferior 

Blotch  on  fruit 

108 

Equal 

Scab  on  foliage 

108-111 

Superior 

Injury  to  foliage 

'12 

Anna 

L.E.F. 

145 

Inferior 

Scab  and  sooty  blotch  on  Jona- 

than apples 

145 

Inferior 

Scab  and  sooty  blotch  on  Wine- 

sap  apples 

145 

Superior 

Eueset  of  Jonathan  apples 

148 

Superior 

Eusset  of  Winesap  apples 

143 

Superior 

Injury  to  foliage 

'12 

Griggsville 

A.J.G 

176 

Inferior 

Scab,    sooty    blotch,    and    fly- 

speck  of  fruit 

176-178 

Superior 

Eusset  on  fruit 

178 

Superior 

Color,  size,  finish,  and  grading 

of  fruit 

175 

Equal 

Scab  on  foliage 

176 

Superior 

Leaf  spot 

From  the  above  tabulation  it  will  be  seen  that  Bordeaux  has  in 
most  of  the  experiments  proved  superior  to  lime  sulfur  as  a  fungicide. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  191 

In  six  different  experiments  Bordeaux  proved  superior  to  lime  sulfur 
in  the  control  of  scab  on  the  fruit ;  in  two  experiments  the  fungicides 
were  equal  in  this  respect.  Lime  sulfur,  however,  was  not  superior  in 
any  case.  In  two  experiments  Bordeaux  proved  superior  to  lime  sul- 
fur in  the  control  of  scab  on  the  foliage.  In  four  experiments  the  con- 
trol of  scab  on  the  foliage  was  equal.  Lime  sulfur  was  in  no  case  su- 
perior to  Bordeaux  in  the  control  of  scab  on  the  foliage.  In  six  ex- 
periments Bordeaux  was  superior  to  lime  sulfur  in  the  control  of 
blotch,  sooty  blotch,  and  flyspeck  fungi.  In  no  case  was  lime  sulfur 
superior  or  equal  to  Bordeaux  in  the  control  of  these  diseases.  In  only 
one  experiment  is  lime  sulfur  reported  as  showing  a  control  superior  to 
Bordeaux  on  a  fungous  disease  of  the  foliage.  In  the  experiments  at 
Griggsville  in  1912,  leaf  spot  (Sphaeropsis  malorum)  was  more  in  evi- 
dence on  the  trees  sprayed  with  Bordeaux  than  on  the  trees  sprayed 
with  lime  sulfur. 

Lime  sulfur,  however,  proved  superior  to  Bordeaux  in  the  major- 
ity of  the  experiments  in  respect  to  spray  injury  to  the  foliage  and 
fruit.  In  nearly  all  cases  the  foliage  on  the  trees  sprayed  with  lime 
sulfur  was  more  vigorous  than  the  foliage  on  the  Bordeaux-sprayed 
trees,  and  in  most  cases  the  lime-sulfur-sprayed  fruit  was  of  superior 
finish  and  color. 

In  seven  experiments  out  of  nine,  lime  sulfur  proved  superior  to 
Bordeaux  in  its  effect  on  the  vigor  and  abundance  of  foliage  or  in  its 
effect  on  spray  injury.  In  1911  in  the  Neoga  experiments,  lime  sul- 
fur proved  inferior  to  Bordeaux  in  relation  to  spray  injury  to  the 
foliage,  and  in  1912  at  the  same  place,  the  vigor  and  abundance  of 
foliage  on  the  lime-sulfur  and  Bordeaux-sprayed  plats  were  equal.  In 
five  experiments  lime  sulfur  was  superior  to  Bordeaux  as  regards  rus- 
seting  of  the  fruit.  With  the  exception  of  the  experiments  at  Neoga 
in  1911  and  1912,  lime-sulfur-sprayed  fruit  was  more  brightly  colored 
and  more  attractive  in  appearance  than  Bordeaux-sprayed  fruit.  In 
reporting  on  the  experiments  at  Neoga  in  1911  and  1912,  0.  S.  Wat- 
kins,  in  charge  of  these  experiments,  calls  attention  to  the  fact  that 
while  lime-sulfur-sprayed  apples  had  a  higher  finish  and  brighter 
color  than  Bordeaux-sprayed  apples,  the  color  was  not  distributed 
over  so  much  of  their  surface  as  in  the  Bordeaux-sprayed  apples.  He 
concludes  that  the  Bordeaux-sprayed  apples  had  more  color  as  a  whole 
than  the  lime-sulfur-sprayed  apples,  tho  this  color  was  not  so  attrac- 
tive, especially  as  the  apples  hung  on  the  trees.  The  general  conclu- 
sion, however,  which  must  be  derived  from  a  summary  of  all  the  re- 
sults, is  that  the  lime-sulfur-sprayed  apples  were  enough  more  attrac- 
tive than  the  Bordeaux-sprayed  apples  to  give  them  a  higher  com- 
mercial value  on  the  market.  With  two  exceptions  lime-sulfur- 
sprayed  apples  graded  a  larger  proportion  of  No.  1  fruit  than  Bor- 
deaux-sprayed apples,  and  in  one  of  the  exceptional  cases  the  grading 


192  BULLETIN  No.  185  [February, 

of  the  two  was  equal.  In  the  experiment  at  Neoga  in  1911  lime-sulfur- 
sprayed  apples  graded  lower  than  Bordeaux-sprayed  apples. 

The  results  of  the  comparisons  of  Bordeaux  and  lime  sulfur  indi- 
cate, therefore,  a  greater  efficiency  for  Bordeaux  as  a  fungicide  but, 
combined  with  its  excellent  fungicidal  properties,  serious  tendencies 
to  injure  fruit  and  foliage  as  a  result  of  its  application.  Lime  sulfur, 
on  the  other  hand,  exercised  a  fair  degree  of  control  of  fungi  and 
caused  little  damage  to  fruit  or  foliage.  The  comparative  value  of 
the  two  sprays  varied  somewhat  from  year  to  year.  In  1911  lime  sul- 
fur caused  considerable  injury  to  fruit  as  a  result  of  lime-sulfur  burn, 
and  was  slightly  less  efficient  as  a  fungicide  than  Bordeaux.  In  1912 
lime  sulfur  proved  to  be  the  most  desirable  spray  in  every  series  of 
experiments  except  those  performed  at  Neoga,  where  it  was  to  all  in- 
tents and  purposes  equal  to  Bordeaux. 

It  must  be  concluded  from  these  observations  that  Bordeaux  and 
lime  sulfur,  properly  used,  are  both  excellent  sprays  for  the  apple. 
Where  fungous  diseases  are  known  to  be  serious,  as  in  orchards  which 
have  long  been  neglected,  the  orchardist  should  use  the  stronger  fungi- 
cide, viz.,  Bordeaux.  Bordeaux  is  also  advised  for  the  cluster-bud 
spray,  since  it  is  a  more  powerful  fungicide  and  seldom  at  this  stage 
seriously  injures  either  fruit  or  foliage.  In  orchards  previously  cared 
for  the  authors  agree  in  advising  the  use  of  lime  sulfur  for  the  spray 
which  follows  the  fall  of  the  petals,  and  for  the  third  summer  spray, 
which  follows  from  a  week  to  ten  days  after  the  fall  of  the  petals. 

3.  Can  Bordeaux  injury  be  lessened  or  prevented  by  frequent 
sprayings  with  the  same  spray  or  by  maintaining  over  the  Bordeaux 
a  coating  of  lime  thruout  tine,  season? 

Experiments  were  made  to  test  this  point  at  Neoga  in  1910  and 
1911,  and  at  Centralia  and  Griggsville  in  1911.  The  results  of  the  ex- 
periments at  Neoga  in  1910  (page  71)  indicated  that  "injuries  to  foli- 
age and  fruit  following  the  use  of  Bordeaux  were  lessened  by  following 
the  applications  of  Bordeaux  as  soon  as  dry  with  8/100  milk  of  lime. ' ' 
It  was  further  noted  that  "applications  of  milk  of  lime  had  a  stimu- 
lating effect  upon  the  foliage."  The  results  at  Neoga  in  1911  (page  87) 
indicated  that  "injuries  to  foliage  and  fruit  following  the  use  of  Bor- 
deaux were  lessened  (1)  by  following  the  applications  of  Bordeaux 
as  soon  as  dry  with  8/100  milk  of  lime,  and  (2)  by  using  the  drench 
spray  of  Bordeaux." 

At  Centralia  in  1911  (Table  28,  page  135)  Plats  J  and  K,  where  the 
regular  applications  of  Bordeaux  were  followed  immediately  by  sec- 
ond or  sealing-in  applications  of  Bordeaux  and  milk  of  lime  respec- 
tively, showed  no  better  control  of  scab  and  no  less  injury  to  the  fruit 
than  some  of  the  plats  which  were  not  sprayed  with  the  follow-up  ap- 
plications. Foliage  injury  was  more  severe  in  Plats  J  and  K  than  in 
the  other  plats. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  193 

The  experiments  at  Griggsville  in  1911  indicated  (pages  164-165) 
that  second  applications  of  Bordeaux  following  immediately  after  the 
three  regular  applications  did  not  affect  in  any  way  the  amount  of  rus- 
set on  the  fruit.  Applications  of  milk  of  lime  even  appeared  to  increase 
rather  than  reduce  the  amount  of  russeting.  Bordeaux  injury  did  not 
appear  on  the  foliage  until  late  in  September.  Plats  receiving  the  fol- 
low-up sprays  were  as  severely  affected  as  those  which  received  only 
the  regular  applications.  The  foliage  on  all  the  Bordeaux-sprayed 
plats  fell  slightly  prematurely  and  at  the  same  time. 

As  none  of  the  secondary  sprays  gave  extremely  marked  results, 
even  tho  they  showed  some  beneficial  effects  in  certain  of  the  experi- 
ments, it  is  concluded  that  secondary  applications  of  neither  Bor- 
deaux nor  milk  of  lime  can  be  recommended  other  than  in  an  experi- 
mental way. 

4.  Is  it  possible  to  interchange  Bordeaux  and  lime  sulfur,  in  a 
spray  schedule,  to  advantage,  using  Bordeaux  for  one  or  more  appli- 
cations and  lime  sulfur  for  the  remaining  applications  ? 

The  results  of  these  experiments  in  general  indicate  that  Bordeaux 
is  a  more  powerful  fungicide  than  lime  sulfur  but  that  it  frequently 
causes  such  serious  damage  to  fruit  and  foliage  that  its  use  is  not  al- 
ways satisfactory.  Theoretically,  therefore,  it  seemed  possible  that 
Bordeaux  might  be  used  for  the  spray  before  the  bloom,  when  there 
was  little  possibility  of  injuring  the  small,  still  unfertilized  apples, 
and  when  the  foliage  was  so  little  unfolded  as  to  expose  very  little  sur- 
face to  its  action,  as  in  most  seasons  this  spray  is  the  most  effective  one 
in  combating  apple  scab.  This  spray  might  then  be  followed  by  lime 
sulfur  or  Bordeaux,  as  circumstances  might  indicate,  for  later  applica- 
tions, thus  avoiding  the  leaf  injury  and  fruit  russeting  which  accom- 
pany the  later,  particularly  the  second,  applications  of  Bordeaux.  Ex- 
periments were  accordingly  planned  to  compare  all  possible  combina- 
tions of  Bordeaux  and  lime  sulfur  for  the  first  three  applications,  and 
were  carried  out  at  Centralia  and  Griggsville  in  1911,  and  at  Neoga, 
Flora,  and  Griggsville  in  1912. 

The  experiments  at  Centralia  in  1911  showed  that  in  the  control  of 
scab  "The  differences"  between  the  sprayed  plats,  "tho  small,  con- 
sistently favored  Bordeaux  for  the  first  spray."  L.  E.  Foglesong,  in 
charge  of  these  experiments,  reports,  "In  the  season  of  1911,  the  first 
spray  (applied  before  the  blossoms  opened)  was  clearly  the  important 
one  in  the  control  of  scab."  (Page  134.) 

At  Griggsville  in  1911  (Table  44, page  166),  Plat  H,  which  received 
Bordeaux  for  the  first  application  and  lime  sulfur  for  the  second  and 
third  applications,  gave  the  largest  proportion  of  No.  1  apples.  Plats 
sprayed  more  frequently  and  later  with  Bordeaux  showed  a  better  con- 
trol of  sooty  blotch  and  flyspeck,  but  the  fruit  on  these  plats  was  much 
more  russeted  than  on  Plat  H. 


194  BULLETIN  No.  185  [February, 

The  Neoga  experiments  of  1912  indicated  (page  103)  that  "the 
most  satisfactory  treatment  consisted  of  Bordeaux  arsenate  of  lead  for 
the  first  application,  and  lime  sulfur  arsenate  of  lead  for  the  second 
and  third  applications. ' ' 

At  Flora  in  1912  the  use  of  lime  sulfur  for  the  first  three  applica- 
tions gave  better  results  than  any  of  the  combination  sprays,  but  Bor- 
deaux for  the  first  application  with  lime  sulfur  for  the  second  and 
third  ranks  second  in  desirability.  The  relative  amounts  of  injury  to 
the  fruit  caused  by  Bordeaux  at  the  various  applications  is  presented 
in  Table  22,  page  114,  and  shows  that  comparatively  little  was  due  to 
the  first  application. 

The  Griggsville  experiments  in  1912,  like  those  at  Flora,  favored 
spraying  for  the  first  three  applications  with  lime  sulfur  alone,  but 
with  unsatisfactory  results  from  Bordeaux  at  the  first  application 
with  lime  sulfur  for  later  applications,  Table  48,  page  180. 

A.  J.  Gunderson,  in  charge  of  the  experiments  at  Griggsville,  re- 
ports (page  179)  as  follows,  "The  more  seldom  Bordeaux  was  used  and 
the  more  often  lime  sulfur  was  used,  the  better  the  color,  finish,  and 
smoothness  of  the  fruit."  Fruit  receiving  Bordeaux  was  more  se- 
verely russeted  than  fruit  sprayed  with  lime  sulfur,  more  russet  occur- 
ring at  the  first  application  than  from  the  later  sprays  in  these  experi- 
ments. Foliage  injury  occurred  in  all  Bordeaux-sprayed  plats.  Plats 
sprayed  but  once  with  Bordeaux  made  a  good  recovery,  but  plats 
sprayed  more  than  once  failed  to  recover  during  the  remainder  of  the 
season. 

The  general  conclusions  from  these  experiments  are  that  the  use  of 
Bordeaux  for  the  spray  before  the  blossoms  open  is  generally  advis- 
able and  that  lime  sulfur  should  be  used  for  the  second  and  third  sum- 
mer sprays. 

5.  What  is  the  most  effective  and  at  the  same  time  the  most  eco- 
nomical dilution  of  lime  sulfur  as  a  fungicide  spray? 

In  various  experiments  lime  sulfur  has  been  used  at  dilutions  run- 
ning from  3i/£  pounds  of  sulfur  in  100  gallons  of  spray  mixture  (1  gal- 
lon commercial  concentrated  lime  sulfur  testing  33°  Baume  in  80  gal- 
lons of  spray  mixture)  to  13%  pounds  of  sulfur  in  100  gallons  of 
spray  mixture  (1  gallon  commercial  concentrated  lime  sulfur,  testing 
33°  Baume,  in  20  gallons  of  spray  mixture).  As  will  be  seen  from 
Table  55,  the  results  were  somewhat  variable.  Taking  into  considera- 
tion, however,  not  only  the  plats  designed  particularly  to  answer  this 
question,  but  also  all  results  from  plats  sprayed  with  lime  sulfur,  it 
has  been  found  that  lime-sulfur  sprays  containing  from  6  to  8  pounds 
of  sulfur  in  each  100  gallons  of  spray  mixture  give  eminently  satisfac- 
tory results.  Sprays  of  these  strengths  are  obtained  by  using  1  gallon 
of  commercial  concentrated  lime  sulfur  in  from  33  to  40  gallons  of 
water,  or  1  gallon  of  homemade  lime  sulfur  prepared  according  to  the 
Illinois  formula  in  18  to  24  gallons  of  water. 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


195 


TABLE   55. — EFFECTS    OF   VARYING   DILUTIONS    OP   LIME    SULFUR   FOR    SUMMER 

SPRAYS 


| 

3 

Dilutions  of 
lime  sulfur 

Place 

Year 

1 

c 

Pagt 

Compared  with 
lime  sulfur,  1 
gal.  to  40  of 

As  regards 

used 

9 

water  (com.) 

K 

1  to  50   (com.) 

Neoga 

'11 

O.S.W. 

81 

Superior 

Scab 

1  to  20 

Inferior 

Scab 

1  to  80   (com.) 

Neoga 

'IS 

O.S.W. 

100 

Inferior 

Scab 

1  to  60   (com.) 

Inferior 

Scab 

1  to  20   (com.J 

Inferior 

Scab 

1  to  36  (111. 

Griggsville 

'12 

A.J.G. 

184 

Superior 

Scab 

form.) 

1  to  18 

Inferior 

Scab 

1  to  18 

Superior 

Scab 

1  to  14 

Superior 

Scab 

1-33,  1-63  (com.) 

Anna 

'12 

L.E.F. 

149 

Equal 

All  results 

1-53 

6.  Is  homemade  concentrated  lime  sulfur,  prepared  according  to 
to  the  formula:  100  pounds  sulfur,  50  pounds  lime,  50  gallons  water, 
as  efficient  as  the  ordinary  commercial  concentrated  lime  sulfur  f 

Experiments  were  conducted  to  test  this  point  in  1910  at  Neoga 
and  Centralia,  with  results,  as  will  be  seen  from  Table  56,  slightly 
favoring  the  commercial  article.  In  1911  and  1912  the  formula  above 
mentioned  was  abandoned  in  favor  of  the  Illinois  formula,  100  pounds 
sulfur,  50  pounds  lime,  66  gallons  water. 

TABLE  56. — EFFECTS  OF  HOMEMADE  CONCENTRATED  LIME  SULFUR 


Year 

Place 

Experimenter 

Page 

Homemade  concentrated 
lime  sulfur  compared  with 

For  control  of 

Bordeaux 

Commercial 
concentrated 

'10 
'10 

Neoga 
Centralia 

O.S.W. 
L.E.F. 

61-64 
128 

Inferior 

Inferior 
Superior 
Inferior 

Equal 
Slightly  superior 
Equal 
Inferior 
Inferior 

Scab   on   foliage 
Scab  on  fruit 
Foliage  injury 
Foliage  injury 
Scab 

7.  What  is  the  fungicidal  value  of  self-boiled  lime  sulfur,  and 
how  does  it  compare  with  lime  sulfur  made  in  the  usual  manner? 

Self-boiled  lime  sulfur  was  experimented  with  at  Griggsville  in 
1909  and  at  Neoga  in  1910.  Table  57  presented  herewith  shows 
at  a  glance  that  this  spray  proved  inferior  to  lime  sulfur  made  in  the 
usual  way,  and  also  inferior  to  Bordeaux  where  self -boiled  lime  sulfur 


196 


BULLETIN  No.  185 


[February, 


and  Bordeaux  were  compared.  Reference  to  the  reports  of  experi- 
ments for  the  years  1909  and  1910  shows  that  the  experimenters  found 
self -boiled  lime  sulfur  practically  worthless  as  a  fungicide  for  both  the 
fruit  and  foliage  of  the  apple.  It  appeared,  however,  from  the  reports 
of  both  series  of  experiments,  that  the  self-boiled  lime  sulfur  exerted 
some  stimulating  or  beneficial  effects  on  the  health  and  vigor  of  the 
foliage  not  in  any  way  connected  with  its  possible  properties  as  a 
fungicide.  The  foliage  in  the  plats  sprayed  with  self-boiled  lime  sul- 
fur was  noteworthy  for  its  abundance,  dark  green  color,  and  generally 
luxuriant  appearance.  Its  worthlessness  in  the  control  of  apple  scab 
precludes  the  possibility  of  its  being  used  as  a  successful  spray  for 
the  apple. 

TABLE  57. — EFFECTS  OF  SELF-BOILED  LIME  SULFUB 


Year 

Place 

Experimenter 

Page 

Self-boiled  lime  sulfur 
compared  with 

For  control  of 

Bordeaux 

Lime  sulfur 

'09 
'10 

Griggsville 
Neoga 

L.E.F. 
O.S.W. 

121 
122 
61-62 
62-63 

Inferior 

Inferior 
Inferior 
Inferior 
Inferior 

Scab  on  fruit 
Scab  on  foliage 
Scab  on  foliage 
Scab  on  fruit 

8.  Will  the  addition  of  copper  sulfate  to  lime  nulfur  increase  the 
fungicidal  value  of  the  spray? 

In  an  effort  to  increase  the  fungicidal  properties  of  lime  sulfur,  cop- 
per-sulfate  solution  was  added  to  this  spray  and  tested  in  1911  at 
Neoga,  Centralia,  and  Griggsville,  and  in  1912  at  Flora.  The  ex- 
periments at  Neoga  (page  87)  showed  that  "lime  sulfur  arsenate  of 
lead  in  combination  with  copper  sulfate  gave  an  efficient  spray  and 
caused  no  injury  to  either  fruit  or  foliage."  The  experiments  at 
Centralia  (pages  134  and  137),  showed  that  the  addition  of  copper  sul- 
fate in  considerable  quantities  (8  pounds  in  100  gallons)  resulted  in 
a  marked  reduction  in  the  amount  of  sooty  blotch,  but  that  it  was  not 
more  efficient  than  lime  sulfur  alone  in  the  control  of  other  diseases. 
Moreover,  it  resulted  in  more  severe  russeting  of  the  fruit  than  lime 
sulfur  alone  in  the  experiments  at  Griggsville,  reported  on  page  170. 
The  addition  of  copper  sulfate  failed  to  produce  any  marked  increase 
in  the  fungicidal  properties  of  the  spray,  and  it  resulted  in  more  rus- 
seting of  the  fruit,  the  amount  of  russeting  increasing  with  the  amount 
of  copper  sulfate  added. 

At  Flora  in  1912  copper  sulfate  was  added  to  lime  sulfur  only  for 
the  application  of  spray  made  before  the  bloom.  The  application  was 
no  more  efficacious  than  that  of  lime  sulfur  alone  in  the  control  of  scab. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  197 

and  it  resulted  in  an  unusually  severe  russeting  of  the  fruit  (page  116). 
It  is  concluded,  therefore,  that  the  addition  of  copper  sulfate  to 
lime  sulfur  does  not  add  to  its  usefulness  as  a  spray.  In  three  of  the 
experiments  reported  on,  it  resulted  in  more  or  less  severe  injury  to 
Ihe  fruit. 

9.  Is  an  application  of  lime  sulfur  made  at  the  strength  used  for 
San  Jose  scale,  applied  while  the  trees  are  dormant,  of  any  value  as 
a  preventive  of  apple  scab  ? 

Experiments  were  made  bearing  upon  this  point  at  Centralia  and 
Griggsville  in  1911,  and  at  Neoga  in  1912.  The  results  of  the  experi- 
ments at  Centralia  (page  137)  indicate  that  "there  is  no  evidence  to 
show  that  the  dormant-tree  application  exerted  any  influence  in  check- 
ing the  development  of  scab."  Experiments  at  Griggsville  bore  out 
those  at  Centralia.  On  page  161  it  is  stated  that  Table  41  shows  that 
"the  dormant-tree  application  of  lime  sulfur  had  no  effect  on  apple 
scab."  The  experiments  on  this  point  at  Neoga  in  1912,  reported  in 
Table  13,  page  91,  indicate  that  a  winter  application  is  of  doubtful 
benefit.  The  average  infection  of  scab  in  the.  winter-sprayed  plats 
amounted  to  22  percent  as  compared  with  an  average  infection  of  25 
percent  on  those  which  did  not  receive  the  winter  application. 

In  all  of  the  experiments  reported,  the  winter  applications  were 
followed  later  by  the  regular  summer  sprays.  The  authors  are,  there- 
fore, of  the  opinion  that  it  is  possible,  in  spite  of  the  results  presented, 
that  winter  applications  might  have  exercised  some  degree  of  control 
over  scab  which  could  not  be  detected  in  comparison  with  other  plats, 
owing  to  the  fact  that  they  received  all  the  sprays  that  were  absolutely 
necessary  for  the  control  of  this  disease.  To  test  this  point  it  would 
be  necessary  to  give  only  a  winter  application  which  should  not  later 
be  followed  by  the  regular  summer  sprays.  As  the  regular  summer 
sprays  could  not,  of  course,  be  abandoned,  the  results  of  the  experi- 
ment bearing  on  this  point  lead  to  the  inevitable  conclusion  that  the 
dormant-tree  spray  with  lime  sulfur  is  unnecessary  for  the  control  of 
the  apple  scab. 

10.  What  is  the  most  effective  poison  which  can  be  combined  ad- 
vantageously with  standard  fungicides  for  the  control  of  chewing  in- 
sects, particularly  the  codling  moth  and  the  plum  curculio? 

Paris  green  and  arsenate  of  lead  were  the  only  insecticides  experi- 
mented with.  These  were  compared  in  plats  at  Griggsville  in  1909, 
and  the  results  are  tabulated  in  Table  26,  page  124.  Paris  green  proved 
less  effective  than  arsenate  of  lead  and  caused  considerable  foliage  in- 
jury. When  used  separately,  as  in  Group  1  of  the  Griggsville  experi- 
ments in  1909,  Paris  green  and  arsenate  of  lead  gave  practically  equal 
control  of  codling  moth,  tho  arsenate  of  lead  proved  superior  in  pre- 
venting injury  from  curculio.  Paris  green  caused  very  serious  foliage 
injury  in  Plats  8  and  10,  and  considerable  injury  in  Plat  9. 


198  BULLETIN  No.  185  [February, 

As  these  results  confirmed  previous  experiments  and  more  or  less 
universal  experience,  further  tests  with  Paris  green  were  considered 
unnecessary  and  experiments  with  this  insecticide  were  accordingly 
abandoned. 

When  experiments  with  copper  ferrocyanide  were  commenced,  it 
was  thought  that  this  spray  might  possess  some  poisoning  qualities 
which  would  make  it  useful  as  an  insecticide.  It  was  not,  of  course, 
used  in  combination  with  Bordeaux  or  lime  sulfur,  as  the  spray  was 
designed  as  a  fungicide.  It  may  be  noted,  however,  that  copper  ferro- 
cyanide failed  to  show  any  decided  qualities  as  a  poison  spray. 

11.  Does  arsenate  of  lead  when  used  alone  possess  any  fungicidal 
value  f 

Experiments  bearing  upon  this  point  are  reported  from  Neoga 
in  both  1911  and  1912,  and  from  Griggsville  in  1911.  The  first  of  these 
experiments  in  1911  at  Neoga  appeared  to  show  that  arsenate  of  lead 
when  used  alone  did  exercise  some  fungicidal  action,  but  was  respon- 
sible for  considerable  foliage  injury  (page  87).  The  experiments  of 
1912,  however,  lead  to  the  following  conclusion  (page  103)  :  "Arsenate 
of  lead  alone  possesses  practically  no  fungicidal  value  and  should 
never  be  used  except  in  combination  with  a  fungicide. ' '  The  Griggs- 
ville experiments  for  1911  reported  on  page  171  confirm  these  results 
(arsenate  of  lead  had  practically  no  fungicidal  value). 

12.  Does  arsenate  of  lead  when  added  to  Bordeaux  or  lime  sulfur 
increase  their  fungicidal  value? 

Experiments  at  Neoga  in  1911  and  1912  showed  (pages  87  and  103) 
that  a  mixture  of  lime  sulfur  and  arsenate  of  lead  was  more  efficient 
in  preventing  apple  scab  than  lime  sulfur  used  alone.  In  fact,  in  1912 
O.  S.  Watkins  reports :  ' '  Lime  sulfur  arsenate  of  lead  is  a  very  much 
more  efficient  fungicide  than  lime  sulfur  alone. ' ' 

The  experiments  at  Anna  in  1912  (page  150)  indicated  that  "the 
neutral  and  mixed  arsenates  of  lead  did  not  add  to  the  effectiveness 
of  lime  sulfur  in  the  control  of  scab. ' '  Acid  arsenate  of  lead  added 
to  lime  sulfur  appeared  to  improve  the  fungicidal  value  of  the  spray 
for  the  control  of  this  disease.  The  addition  of  all  kinds  of  arsenate 
of  lead  to  lime  sulfur  gave  a  spray  superior  to  lime  sulfur  alone  for 
the  control  of  sooty  blotch. 

At  Griggsville  in  1912  (page  186)  "lime  sulfur  arsenate  of  lead 
was  slightly  more  effective  in  controlling  scab,  flyspeck,  and  sooty 
blotch  than  lime  sulfur  alone. ' ' 

Thruout  the  experiments  in  general,  the  addition  of  arsenate  of 
lead  to  Bordeaux  added  nothing  to  its  fungicidal  value. 

It  is  concluded,  therefore,  that  the  addition  of  arsenate  of  lead  to 
lime  sulfur  increases  its  fungicidal  value,  while  the  addition  of  arsen- 
ate of  lead  to  Bordeaux  does  not  improve  the  fungicidal  value  of  the 
resulting  spray. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  199 

13.  Are  there  differences  between  various  brands  of  arsenate  of 
lead  which  would  make  one  brand  more  useful  than  another,  either 
alone,  or  in  combination  with  the  standard  fungicides  ? 

Various  brands  of  arsenate  of  lead  have  been  used  alone  or  in  com- 
bination with  standard  fungicides  at  Neoga  and  Centralia  in  1910,  at 
Neoga  in  1911,  and  at  Anna  in  1912. 

The  experiments  at  Neoga  in  1910  (page  71)  indicated  that  "for 
use  with  lime-sulfur  solution,  neutral  or  ortho  arsenate  of  lead  gave 
better  results  than  arsenates  of  lead  containing  higher  percentages  of 
arsenic  oxid. ' '  No  results  were  obtainable  at  Centralia  in  1910. 

In  1911  the  experiments  at  Neoga  showed  rather  insignificant  dif- 
ferences between  the  various  brands  of  arsenate  of  lead,  but  0.  S. 
Watkins,  in  charge  of  these  experiments,  states  that ' '  altho  the  results 
recorded  in  the  different  columns  do  not  show  wide  variation  between 
the  different  plats,  they  are  in  accord  with  those  obtained  in  1910, 
which  showed  that,  in  combination  with  lime-sulfur  solution,  the  neu- 
tral arsenate  of  lead  produced  a  spray  which  was  more  efficient  and 
safer  to  use  than  those  arsenates  of  lead  higher  in  arsenic  oxid. ' ' 

At  Anna  in  1912  (pages  150  and  152)  acid  arsenate  of  lead  used 
with  lime  sulfur  showed  a  small  but  consistent  lessening  in  the  amount 
of  scab  and  sooty  blotch  over  mixed  and  neutral  brands.  All 
brands  effectively  controlled  codling  moth,  but  inconsistent  differences 
appeared  in  the  control  of  curculio.  The  various  classes  of  arsenate 
of  lead  when  used  in  combination  with  Bordeaux  showed  no  important 
differences  in  the  control  of  diseases,  insects,  or  injuries  to  the  fruit. 

It  was  found  that  arsenates  of  lead  were  more  efficient  used  in 
combination  with  the  fungicides  than  alone,  and  that  they  caused  less 
foliage  injury. 

14.  Of  what  value  are  certain  new  sprays  both  as  fungicides  and 
as  insecticidesf 

Among  the  new  sprays  experimented  with  were  copper  ferrocyan- 
ide,  Cucasa,  and  Sulfocide.  Of  these,  Sulfocide  proved  unsatisfactory, 
as,  when  used  in  combination  with  Paris  green,  it  severely  injured  the 
foliage  (report  of  spraying  experiments  at  Neoga,  in  1911,  0.  S. 
Watkins,  page  87).  Cucasa  proved  almost  as  efficient  as  Bordeaux, 
caused  no  russeting  of  the  fruit,  but  was  somewhat  injurious  to  foli- 
age (page  87).  Not  being  more  efficient  than  Bordeaux,  this  spray 
was  also  abandoned. 

Copper  ferrocyanide  made  by  combining  copper  sulfate  and  potas- 
sium cyanide  seemed  to  possess  advantages,  both  from  the  theoretical 
and  practical  standpoint,  that  made  it  seem  advisable  to  test  this  spray 
somewhat  more  thoroly.  Experiments  were  accordingly  conducted 
with  copper  ferrocyanide  at  Neoga  in  1911,  and  at  Anna,  Flora,  and 
Griggsville  in  1912.  Table  58  presents  a  summary  of  results  from  the 
use  of  this  spray. 


200 


BULLETIN  No.  185 


[February, 


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1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  201 

In  1911  copper  ferrocyanide  proved  superior  to  Bordeaux  and  lime 
sulfur  with  regard  to  the  vigor  of  the  foliage,  and  superior  to  Bor- 
deaux with  regard  to  the  grading  of  the  fruit.  It  was  inferior  to  Bor- 
deaux in  the  control  of  scab  on  the  fruit.  At  Flora  in  1912  it  again 
proved  superior  to  both  Bordeaux  and  lime  sulfur  with  regard  to  vigor 
and  abundance  of  foliage,  and  it  also  caused  less  foliage  injury.  It 
was  equal  to  Bordeaux  and  lime  sulfur  in  the  control  of  scab  on  the 
fruit,  but  inferior  in  the  control  of  blotch,  sooty  blotch,  and  flyspeck. 
It  caused  less  russet  than  Bordeaux,  but  more  than  lime  sulfur.  In 
the  experiments  at  Anna  it  proved  inferior  in  the  control  of  scab,  sooty 
blotch,  and  flyspeck  to  both  Bordeaux  and  lime  sulfur.  It  caused  less 
russeting  of  the  fruit  than  Bordeaux,  but  more  than  lime  sulfur.  The 
most  discouraging  results  from  this  spray  are  reported  from  Griggs- 
ville,  where  it  was  tried  on  several  plats  and  at  various  strengths,  both 
in  combination  with  an  insecticide  and  separately.  In  this  entire 
series  of  experiments  copper  ferrocyanide  appeared  to  be  worthless. 

It  is  believed  by  the  authors  of  this  bulletin  that  this  spray  is 
worthy  of  further  investigation,  but  the  results  thus  far  obtained  do 
not  warrant  recommending  copper  ferrocyanide  other  than  in  an  ex- 
perimental way. 

15.  How  often  and  at  what  times  should  summer  sprays  ~be  ap- 
plied f 

Experiments  bearing  directly  on  these  points  were  performed  at 
Griggsville  in  1909,  at  Neoga  and  Griggsville  in  1911,  and  at  Neoga 
and  Anna  in  1912. 

The  results  at  Griggsville  in  1909  emphasized  the  importance  of 
the  spray  applied  immediately  after  the  fall  of  the  petals.  The  spray 
applied  at  this  time  reduced  codling-moth  injury  from  17  percent  on 
the  unsprayed  plat  to  3  percent  on  the  sprayed  plat;  it  reduced 
scab  from  89  percent  on  the  check  to  49  percent  on  the  sprayed  plat. 
Altho  there  was  less  injury  from  codling  moth  in  the  plat  sprayed  once 
before  the  bloom  than  in  the  check  plat,  the  difference  could  scarcely 
be  due  to  the  effect  of  the  spray,  and  this  spray  apparently  reduced 
scab  from  89  to  85  percent  only.  (See  Table  25,  page  123.) 

In  1911,  at  Neoga,  plats  were  sprayed  three,  four,  and  five  times. 
The  fourth  application  of  homemade  lime  sulfur  reduced  scab  from 
51  to  44  percent,  and  the  fifth  application  further  reduced  it  to  31 
percent.  Commercial  lime  sulfur  reduced  scab  from  39  to  28  percent 
at  the  fourth  application,  but  no  further  reduction  appeared  to  fol- 
low the  fifth  application.  The  fourth  application  of  Bordeaux  did  not 
seem  to  reduce  scab,  but  a  fifth  application  reduced  scab  from  25  to 
15  percent  (Table  6,  page  76).  The  irregular  character  of  these  re- 
sults is  probably  traceable  to  the  different  sticking  qualities  of  the 
fungicides.  Bordeaux  from  the  early  sprays  remained  on  the  trees 
long  enough  to  make  a  fourth  application  unnecessary.  The  fifth  ap- 
plication, however,  was  made  at  a  time  when  the  coating  of  Bordeaux 
was  disappearing  and  in  time  to  lessen  damage  from  a  comparatively 
late  attack  of  scab. 


202  BULLETIN  No.  185  [February, 

The  experiments  at  Griggsville  in  1911  (Table  43,  page  166)  gave 
the  following  results:  The  addition  of  three  extra  summer  sprays  (six 
in  all)  resulted  in  a  slightly  better  control  of  curculio,  but  did  not  in- 
crease the  production  of  No.  1  apples  to  any  considerable  extent.  Scab, 
sooty  blotch,  and  flyspeck  were  almost  perfectly  controlled  by  the  first 
three  sprays:  it  appeared,  therefore,  that  the  additional  applications 
were  unnecessary  in  1911. 

The  Neoga  experiments  in  1912  (Table  14,  page  93)  indicated, 
' '  The  use  of  more  than  three  applications  seemed  unnecessary  in  1912, 
as  the  variation  between  the  percentages  of  No.  1  apples  in  the  differ- 
ent plats  is  neither  regular  enough  nor  varied  enough  to  permit  draw- 
ing definite  conclusions." 

In  the  experiments  at  Anna  in  1912  (Table  31,  page  146)  the  first 
application  reduced  codling  moth  slightly,  the  check  plat  showing  30 
percent  and  the  sprayed  plats  18  and  24  percent  respectively  for  lime 
sulfur  arsenate  of  lead  and  Bordeaux  arsenate  of  lead.  Curculio  were 
unaffected  by  the  first  application.  Scab  was  reduced  from  83  to  63 
and  69  percent  respectively  in  the  lime-sulfur  and  Bordeaux-sprayed 
plats.  The  second  application  resulted  in  the  reduction  of  codling- 
moth  injury  from  18  to  11  percent  in  the  lime  sulfur  arsenate  of  lead 
plat,  and  from  24  to  17  percent  in  the  Bordeaux  arsenate  of  lead  plat. 
Curculio  were  again  unaffected  by  this  spray.  Scab  was  not  affected 
by  lime  sulfur  at  this  application,  but  Bordeaux  showed  a  reduction 
from  83  to  63  percent.  The  third  application  alone  was  slightly  less 
effective  in  controlling  the  codling  moth  than  the  second,  and  slightly 
more  effective  than  the  first.  Its  effects  on  curculio  and  scab  were 
negligible. 

The  omission  of  the  first  spray  proved  serious  in  the  control  of  scab, 
and  the  omission  of  the  second  spray  was  equally  unfavorable  in  the 
case  of  the  codling  moth.  In  this  series  of  experiments  the  omission  of 
the  third  spray  where  Bordeaux  was  used  for  the  first  and  second 
sprays  did  not  prove  serious,  but  the  omission  of  the  third  applica- 
tion where  lime  sulfur  was  used  for  the  first  two  sprays  was  found 
inadvisable. 

The  addition  of  a  fourth  spray  reduced  injury  from  codling  moth, 
curculio,  and  sooty  blotch,  but  did  not  affect  scab.  Five  applications 
further  reduced  curculio  injury  but  did  not  affect  codling  moth,  apple 
scab,  or  sooty  blotch. 

In  general,  it  was  found  that  thq  first  three  summer  sprays  were 
the:  most  useful  in  improving  the  general  grade  and  quality  of  the 
fruit  by  controlling  the  majority  of  the  insects  and  fungi ;  that  none  of 
these  sprays  could  be  omitted  safely;  and  that  the  addition  of  the 
fourth  and  fifth  sprays  assisted  in  controlling  late-brood  codling  moth 
and  injury  from  curculio. 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  203 

16.  What  are  the  relative  advantages  and  disadvantages  of  apply- 
ing large  and  small  quantities  of  Bordeaux? 

Experiments  bearing  upon  this  question  were  performed  both  at 
Griggsville  in  1911  and  at  Anna  in  1912.  The  first  of  these  (pages  163 
and  164)  indicated  that  light  and  heavy  sprayings  were  equally  effec- 
tive in  the  control  of  apple  scab ;  that  heavy  applications  controlled 
sooty  blotch  and  flyspeck  fungi  and  codling  moth  and  curculio  more 
efficiently  than  the  light  applications.  Fruit  receiving  the  heavy  appli- 
cations, however,  was  poorer  in  color  and  more  severely  russeted  than 
fruit  receiving  the  light  applications.  These  latter  differences  about 
counterbalanced  the  former  advantages,  the  grading  from  the  two  be- 
ing practically  equal.  . 

In  the  experiments  at  Anna  in  1912  (page  150),  heavy  applications 
of  Bordeaux  arsenate  of  lead  were  more  efficient  as  a  protection  against 
curculio  and  scab  than  lighter  applications,  equally  efficient  in  the 
control  of  sooty  blotch,  and  equally  inefficient  in  the  control  of  codling 
moth,  but  they  resulted  in  more  russeting  of  the  fruit  than  the  light 
applications. 

On  the  whole,  these  experiments  indicate  that  a  thin  but  complete- 
coating  of  the  fruit  and  foliage  with  Bordeaux  arsenate  of  lead  is  more 
desirable  than  a  heavy  coat,  except  in  cases  where  special  protection 
from  curculio  is  necessary. 

INCIDENTAL  OBSERVATIONS 

Included  under  this  heading  are  various  observations  which  can- 
not readily  be  tabulated,  and  which  were  incidental  to  the  principal 
lines  of  inquiry.  They  are  put  together  under  this  heading  for  con- 
venient reference. 

1.  Owing  to  the  danger  of  russeting  the  fruit  as  a  result  of  appli- 
cations of  Bordeaux,  it  is  a  more  or  less  common  practice  to  omit  the 
fungicide  from  the  spray  following  the  fall  of  the  petals,  as  this  spray 
is  applied  more  particularly  for  the  control  of  codling  moth.    It  has, 
however,  been  found  inadvisable  to  omit  the  fungicide,  as  an  infection 
of  scab  is  very  likely  to  occur  at  this  time. 

2.  In  several  experiments  lime  sulfur  appeared  to  attract  codling 
moth  and  to  repel  curculio.    The  former  effect  was  more  marked  than 
the  latter,  but  both  facts  were  observed  with  a  considerable  degree  of 
consistency  thruout  the  progress  of  the  experiments. 

3.  Various  quantities  of  arsenate  of  lead  were  used  in  an  attempt 
to  find  the  most  efficient  killing  spray.  Four  pounds  of  paste  arsenate 
of  lead  in  100  gallons  of  spray  mixture  was  found  efficient  and  econom- 
ical. 

4.  Adding  the  sludge,  which  remained  after  the  preparation  of 
concentrated  lime  sulfur,  to  the  spray  mixture  did  not  improve  or  im- 
pair the  efficiency  of  the  spray. 


204  BULLETIN  No.  185  [February, 

Recommendations 

As  a  result  of  the  spraying  experiments  detailed  in  this  bulletin, 
and  also  from  other  experience  and  recommendations,  the  authors  rec- 
ommend that  apple  trees  be  sprayed  at  the  times  and  in  the  manner 
indicated  below. 

1.  Dormant-tree  spray. — This  spray  is  used  particularly  for  the 
control  of  San  Jose  scale.    It  is  applied  in  the  fall  after  the  leaves 
drop  or  in  the  spring  before  the  buds  open,  preferably  at  the  latter 
time.  Where  San  Jose  scale  is  present  or  is  known  to  infest  a  certain 
locality,  this  spray  is  a  necessity,  and  it  is  advised  as  a  matter  of  pre- 
caution in  all  orchards  thruout  the  state. 

The  dormant-tree  spray  should  be  either  commercial  or  homemade 
lime  sulfur.  The  commercial  lime  sulfur  testing  33°  Baume  should 
be  used  at  the  rate  of  11  gallons  of  commercial  lime  sulfur  to  89  gal- 
lons of  water,  or  11  gallons  of  commercial  lime  sulfur  in  100  gallons  of 
the  spray.  This  is  equivalent  to  1  gallon  of  commercial  lime  sulfur  to  8 
gallons  water.  The  homemade  lime  sulfur,  made  according  to  the 
Illinois  formula,  described  on  page  54,  is  used  at  the  rate  of  20  gal- 
lons of  stock  solution  homemade  lime  sulfur  to  80  gallons  of  water,  or 
20  gallons  of  homemade  lime  sulfur  in  100  gallons  of  spray. 

2.  First  summer  application. — This  spray  is  used  particularly  for 
the  control  of  apple  scab.    As  a  secondary  object,  however,  it  is  used 
to  kill  the  various  leaf -eating  insects  which  appear  early  in  the  season, 
including  bud  moth,  tent  caterpillar,  and  canker  worm.    These  insects, 
tho  not  always  present  in  large  numbers,  are  likely  to  cause  serious 
damage  and  must  be  guarded  against. 

The  first  summer  application  is  made  after  the  cluster  buds  open, 
as  soon  as  the  individual  flower  buds  spread  apart,  but  before  the 
flower  buds  themselves  open.  In  large  commercial  orchards  it  will  be 
found  necessary  to  begin  spraying  before  all  the  individual  flower 
buds  have  spread  apart,  in  order  to  complete  spraying  before  the  first 
blossoms  open.  Spraying  may  be  continued  at  this  time  until  the 
petals  have  commenced  to  separate,  but  should  be  discontinued  as  soon 
as  the  stamens  and  pistils  of  the  flowers  are  exposed. 

Bordeaux,  prepared  according  to  the  formula,  8  pounds  copper 
sulfate,  8  pounds  freshly  slaked  lump  lime,  and  100  gallons  of  water, 
with  4  pounds  arsenate  of  lead  added  as  an  insecticide,  is  the  best 
spray  for  use  at  this  time.  The  preparation  of  this  spray  is  described 
on  page  54. 

3.  Second  summer  application. — This  spray  is  used  particularly 
for'  the  control  of  the  codling  moth,  but  is  of  almost  equal  importance 
as  a  preventive  of  apple  scab.     Incidentally,  it  is  advantageous  as  a 
protection  against  various  leaf-eating  insects. 

It  is  applied  immediately  after  the  fall  of  the  petals,  while  the  lobes 
of  the  calyx  are  still  distended.  The  greater  number  of  the  first  brood 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  205 

of  the  codling  moth  enter  the  apple  thru  the  calyx  end.  By  spraying 
the  trees  while  the  calyx  cups  are  still  open,  poison  will  be  placed  on 
the  base  of  the  lobes  and  stamens  and  sometimes  within  the  cup  itself, 
where  the  larvae  of  the  codling  moth  are  reasonably  sure  to  get  it  when 
entering  the  apple.  At  this  stage  the  small  apples  point  upward  or 
outward,  and  the  calyxes  are  easily  coated  with  poison. 

For  this  application  lime  sulfur  arsenate  of  lead,  using  2i/^  gallons 
of  commercial  concentrated  lime  sulfur,  or  5  gallons  of  homemade  lime 
sulfur  (Illinois  formula,  page  54)  in  100  gallons  of  spray,  is  recom- 
mended. 

4.  Third  summer  application. — This  is  used  as  an  additional  pre- 
caution against  apple  scab  and  codling  moth.    It  is  also  a  safeguard 
against  leaf-eating  insects,  and  to  some  extent  against  certain  fungous 
diseases  which  appear  later  in  the  season,  including  blotch,  sooty 
blotch,  flyspeck,  and  leaf  spot  (SpTiaeropsis  malorum). 

This  spray  should  be  made  about  ten  days  after  the  second  sum- 
mer application.  In  large  orchards  the  second  spray  would  in  all  prob- 
ability not  be  completed  at  one  end  of  the  orchard  until  it  was  time  to 
commence  the  third  summer  application  at  the  other.  The  best  spray 
for  this  application  appears  to  be  lime  sulfur  arsenate  of  lead. 

5.  Fourth  summer  application. — This  spray  is  applied  as  a  safe- 
guard against  apple  blotch  and  codling  moth.     It  is  applied  two  to 
three  weeks  after  the  third  summer  spray.    Bordeaux  arsenate  of  lead 
should  be  used  in  hot  dry  weather ;  lime  sulfur  arsenate  of  lead  should 
be  used  in  cool  weather. 

6.  Fifth  summer  application. — This  spray  is  particularly  for  the 
control  of  the  second  brood  of  codling  moth,  and  incidentally  for  the 
prevention  of  curculio  injury,  blotch,  sooty  blotch,  flyspeck,  and  leaf 
spot. 

It  is  made  approximately  ten  weeks  after  the  bloom,  or  at  times 
varying  from  the  last  week  in  June  in  the  extreme  southern  part  of 
Illinois  to  August  1  in  the  northern  part  of  the  state. 

For  this  spray  arsenate  of  lead  and  lime  should  be  used.  Where 
fungous  injury  is  anticipated,  Bordeaux  arsenate  of  lead  may  be  sub- 
stituted. *{ 

7.  Extra  sprays. — Extra  sprays  are  chiefly  used  as  safeguards 
against  bitter  rot.    Where  this  disease  is  anticipated,  spraying  should 
begin  the  last  week  in  June,  and  should  be  followed  at  intervals  of  ten 
days  until  four  applications  have  been  made.    Bordeaux  is  the  proper 
fungicide  to  use  for  this  disease.    It  is  prepared  in  the  same  manner 
as  for  the  first  summer  application.    If  no  preventive  measures  have 
been  taken  against  bitter  rot,  and  the  disease  appears  suddenly  and 
unexpectedly,  spraying  should  be  commenced  without  a  moment's  de- 
lay as  soon  as  the  presence  of  the  disease  is  discovered. 


206 


BULLETIN  No.  185 


[February, 


o 


o 

g 

o 

w 

OQ 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  207 


PLATE  2. — BURN  DUE  TO  SPRAYING  WITH  LIME  SULFUR  DURING  VERY  HOT 

WEATHER 


208 


BULLETIN  No.  185 


[February, 


PLATE  3. — UNSPRAYED  TREES,  OCTOBER  2,  1912;  ADJOINING  TREES  SHOWN  IN 

PLATE  4 


PLATE  4. — SPRAYED  TREES,  OCTOBER  2,  1912;  ADJOINING  TREES  SHOWN  IN  PLATE  3 
THE  PICTURES  IN  PLATES  3  AND  4  WERE  TAKEN  FROM  THE  SAME  SPOT 


1916] 


FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS 


209 


PLATE  5. — GRIGGSVILLE  EXPERIMENTS,  1912 

A.  TREE  SPRAYED  WITH  BORDEAUX 

B.  TREE  SPRAYED  WITH  LIME  SULFUR 


PLATE  6. — GRIGGSVILLE  EXPERIMENTS,  1912 

A.  APPLES  SPRAYED  WITH  BORDEAUX 

B.  APPLES  SPRAYED  WITH  LIME  SULFUR 


210 


BULLETIN  No.  185 


[February, 


PLATE  7a. — GRIGGSVILLE  EXPERIMENTS,  1912 
APPLES  SPRAYED  WITH  LIME  SULFUR 


PLATE  7b. — GRIGGSVILLE  EXPERIMENTS,  1912 
APPLES  SPRAYED  WITH  BORDEAUX 


1916]  FIELD  EXPERIMENTS  IN  SPRAYING  APPLE  ORCHARDS  211 


PLATE  8. — BLOSSOM  BUDS  EEADY  FOR  APPLICATION  OF  FIRST  SPRAY 


212 


BULLETIN  No.  185 


[February, 


PLATE  9. — THE  PROPER  CONDITION  AND  TIME  FOR  THE  SECOND  SUMMER  SPRAT; 
THE  CALYX  CUPS  ARE  STILL  OPEN  AND  THE  FRUITS  POINT  UPWARD  AND  OUTWARD 


PLATE  10. — THE  PROPER  CONDITION  AND  TIME  FOR  THE  THIRD  SUMMER  SPRAY 


UNIVERSITY  OF  ILLINOIS-URBANA 


